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Showing papers on "Prolactin published in 1974"


Journal ArticleDOI
TL;DR: Groups of female rats were decapitated at 3-hr intervals throughout 4-day estrous cycles and the plasma of each rat was assayed for LH, FSH, prolactin, progesterone and estradiol-17β, which exhibited a peak concentration in plasma on the day of proestrus.
Abstract: Groups of female rats were decapitated at 3-hr intervals throughout 4-day estrous cycles and the plasma of each rat was assayed for LH, FSH, prolactin, progesterone and estradiol-17β. Radioimmunoassays were used to measure these hormones, except for progesterone which was determined by the competitive protein binding assay. All five hormones exhibited a peak concentration in plasma on the day of proestrus. In addition, progesterone was elevated from 0900 hr of metestrus to 0900 hr of diestrus, while plasma prolactin showed a brief rise at 1500 hr of estrus. The elevated level of estradiol on the day of proestrus followed a different pattern than the other four hormones. Estradiol concentration began to rise late on metestrus, reached a peak at noon of proestrus, and fell before peak levels of the other hormones were reached. The preovulatory elevation of LH, prolactin and progesterone occurred between noon and midnight of proestrus, while the peak of FSH lasted from noon of proestrus to noon of estrus. (E...

1,310 citations


Journal ArticleDOI
TL;DR: Apomorphine, an agent known to mimic the effects of dopamine, caused a significant decrease in the amount of radioactive and radioimmunoassayable prolactin released int...
Abstract: A study of the in vitro effect of dopamine on the release of newly synthesized prolactin is reported. Pituitary glands of female rats were incubated with 4,5-3H-leucine and the radioactive prolactin present in the pituitary gland and that released into the incubation medium were measured. Incubation with 5 × l 10–7M dopamine caused an 85% decrease in prolactin release. Prior injection of the rats with perphenazine or haloperidol rendered the pituitary gland refractory to the in vitro inhibitory effect of dopamine. Although in vitro perphenazine and haloperidol had little or no effect on release of prolactin, 5 × 10–9M of these drugs directly blocked the in vitro action of dopamine on prolactin release. Phentolamine, an α-blocking agent, was partially able to block the inhibitory effect, of dopamine. Propranolol, however, was not effective. Apomorphine, an agent known to mimic the effects of dopamine, caused a significant decrease in the amount of radioactive and radioimmunoassayable prolactin released int...

507 citations


Journal ArticleDOI
23 Aug 1974-Nature
TL;DR: It is reported that the production of progesterone by human granulosa cells in vitro requires low physiological concentrations of prolactin whereas high concentrations are inhibitory, and it is still possible that Prolactin could play a ‘permissive’ role, as in other species, where alterations in peripheral blood levels have little effect on luteal activity.
Abstract: PROLACTIN constitutes part of the luteotrophic complex necessary for the maintenance and secretory activity of the corpus luteum in the rat1,2, mouse3, rabbit4, hamster5, ferret6, pig7 and sheep8. Recent evidence suggests, however, that prolactin may have little to do with luteal function in women9–15. Nevertheless, it is still possible that prolactin could play a ‘permissive’ role, as in other species, where alterations in peripheral blood levels, within limits, have little effect on luteal activity. In an attempt to gain more insight into the possible role of prolactin in controlling ovarian activity in women, we have studied the production of steroids by human granulosa cells growing in tissue culture, and the effects of the addition or neutralisation of human prolactin in the culture media. We report that the production of progesterone by human granulosa cells in vitro requires low physiological concentrations of prolactin whereas high concentrations are inhibitory.

431 citations


Journal ArticleDOI
25 May 1974-BMJ
TL;DR: Bromocriptine appears to be the treatment of choice for inappropriate lactation in association with hypogonadism on a long-term basis and low prolactin levels allow resumption of normal gonadal function.
Abstract: Seventeen women and four men with galactorrhoea and associated hypogonadism have been treated with bromocriptine for 2 to 28 months In 18 patients the gonadal status became normal as the galactorrhoea improved The gonadally unresponsive patients had either pituitary tumours or premature menopause Prolactin levels fell with treatment; withdrawal of the drug was associated with an increase in serum prolactin and a recurrence of the galactorrhoea and hypogonadism Two patients tried to become pregnant on treatment and both succeeded Raised prolactin levels appear to block the actions of the gonadotrophins at a gonadal level rather than prevent their synthesis or release; lowering prolactin secretion with bromocriptine allows resumption of normal gonadal function Bromocriptine appears to be the treatment of choice for inappropriate lactation in association with hypogonadism on a long-term basis

361 citations


Journal ArticleDOI
S. Nader1

293 citations


Journal ArticleDOI
TL;DR: Thyroid hormones and somatostatin exhibit summation in their inhibiting effects in a dose-dependent manner, and the injection of TRF leads to a greater rise in both plasma TSH and PRL in estrogen-progesterone-pretreated male rats than in untreated male rats.
Abstract: Somatostatin, a tetradecapeptide isolated from ovine hypothalamic extracts on the basis of its ability to inhibit the spontaneous secretion of growth hormone (GH) by pituitary cell cultures, has been found to inhibit the stimulated secretion of thyrotropin (TSH) mediated by TRF(pGlu-His- Pro-NH2), 10 × [K†], or theophylline in vitro, while having no effect on the secretion of luteinizing hormone (LH) due to LRF. The spontaneous release of PRL in vitro is also inhibited by somatostatin but to a lesser extent than is the spontaneous secretion of GH. In vivo, the TRF-triggered secretion of TSH but not of PRL is suppressed by somatostatin in the estrogen-progesteronepretreated male rat. The injection of TRF leads to a greater rise in both plasma TSH and PRL in estrogen-progesterone-pretreated male rats than in untreated male rats. Somatostatin acts rapidly but reversibly to inhibit the secretion of TSH due to TRF in a dose-dependent manner. Thyroid hormones and somatostatin exhibit summation in their inhibiti...

281 citations


Journal ArticleDOI
TL;DR: Normal male rats were subjected to a variety of stress stimuli including simple handling, transfer from room to room, ether anesthesia alone or combined with bleeding, and the injection of saline or epinep.
Abstract: Normal male rats were subjected to a variety of stress stimuliincluding simple handling, transfer from room to room, ether anesthesia alone or combined with bleeding, the injection of saline or epinep

256 citations


Journal ArticleDOI
TL;DR: In all cases rat hypothalamic extracts significantly inhibited pituitary prolactin (PRL) release in vitro and the catecholamine containing acid eluate from the alumina adsorption procedure was able to inhibit PRL release to the same degree as untreated hypothalamic extract.
Abstract: Rat hypothalamic extracts, dopamine (DA), norepinephrine (NE), and epinephrine (EP), were incubated with rat pituitary tissue in medium 199. In all cases rat hypothalamic extracts significantly inhibited pituitary prolactin (PRL) release in vitro. When the hypothalamic extracts were subjected to preincubation with a rat brain monoamine oxidase enzyme preparation (MAO) or ot aluminum oxide (alumina) catecholamine adsorption, the hypothalamic extracts lost their ability to inhibit PRL release in vitro Pepsin pretreatment did not impair the inhibition of PRL release by hypothalamic extracts and iproniazid 10 μg/ml of medium blocked the effect of MAO on the hypothalamic extracts. The DA and NE content of MAO treated and untreated hypothalamic extracts was measured by a fluorometric technique. The catecholamine containing acid eluate from the alumina adsorption procedure was able to inhibit PRL release to the same degree as untreated hypothalamic extracts. Dopamine (5.26 × 10−9 to 5.26 × 10−7M) and NE (2.42 × ...

255 citations


Journal ArticleDOI
TL;DR: The ontogenesis of specific binding of 125I-labeled insulin, hGH and oPRL was measured in tissues from rat, rabbit and guinea pig and three patterns of125I-insulin binding with respect to development were observed.
Abstract: The ontogenesis of specific binding of 125I-labeled insulin, hGH and oPRL was measured in tissues from rat, rabbit and guinea pig. Binding of 125I-oPRL and 125I-hGH was very low in liver membranes from fetal and immature rats. A 9- fold (oPRL) and 3.5-fold (hGH) increase in binding occurred between 20 and 40 days of age with a greater increase in binding in mid and late pregnancy. Binding to male liver membranes was significantly lower at all stages of development. There were no significant changes in the binding of 125I-hGH from fetal through 30 day rabbit liver membranes. Between 30 and 60 days of age, a 6-fold increase in binding occurred, with a further increase in binding during pregnancy. A similar overall pattern was observed with I25I-bGH. The increase in specific binding of 125I-oPRL was more gradual and occurred earlier than for 125I-GH. In the guinea pig, three patterns of 125I-insulin binding with respect to development were observed. Fetal placenta and kidney showed marked increase in specifi...

241 citations


Journal ArticleDOI
TL;DR: When nursing women were allowed to play with but not nurse their infants, prolactin did not rise in spite of the occurrence of milk let-down, and Substitution of a breast pump for the infant at a regular period of nursing caused prolactIn elevations similar in timing and in magnitude to replacement of the baseline value.
Abstract: The effect of suckling and breast stimulation on plasma prolactin measured by homologous radioimmunoassay has been studied in nursing women, in normal, nonlactating women and men, in chlorpromazine treated women, in pregnant women, and in women with galactorrhea. Nursing women had increased plasma prolactin before nursing during the first 6 weeks postpartum; mean prolactin rose rapidly throughout the period of suckling and reached a peak 8.5 times the baseline value just after the termination of nursing. Women studied between 7 and 28 weeks postpartum had normal prolactin levels before nursing; with suckling they had smaller but significant elevations, averaging 6.0 times the baseline value at the end of nursing. When nursing women were allowed to play with but not nurse their infants, prolactin did not rise in spite of the occurrence of milk let-down. Substitution of a breast pump for the infant at a regular period of nursing caused prolactin elevations similar in timing and in magnitude to thos...

235 citations


Journal ArticleDOI
TL;DR: Receptors for human, simian, ovine, bovine and murine prolactin, human growth hormone and human placental lactogen have been identified in plasma-membrane-containing subcellular particles isolated from rabbit mammary glands.
Abstract: Receptors for human, simian, ovine, bovine and murine prolactin, human growth hormone and human placental lactogen have been identified in plasma-membrane-containing subcellular particles isolated from rabbit mammary glands. The association and dissociation of 125I-labelled prolactin are time- and temperature-dependent processes, both being maximal at 37°C. 125I-labelled prolactin prepared by the enzymic iodination procedure with lactoperoxidase binds better to receptors than does the preparation obtained by using chloramine-t as the oxidizing agent. The binding of 125I-labelled prolactin to receptors is strongly influenced by pH and ionic composition but not by many low-molecular-weight compounds tested, e.g. steroids, nucleotides and several drugs. Receptor activity is sensitive to trypsin and phospholipase C digestion, suggesting that protein and phospholipid moieties are essential for the binding of 125I-labelled prolactin. The binding of 125I-labelled prolactin to receptors is a saturable and reversible process. Scatchard and Lineweaver–Burk analyses suggest that 125I-labelled prolactin has a high affinity for its receptor. Binding of 125I-labelled prolactin to receptors does not result in the destruction of the hormone. Considerable prolactin-binding activity is also observed in subcellular fractions isolated from the adrenal gland, liver, ovary and kidney of the pregnant rabbit, a finding that is consistent with other reported actions of prolactin in these organs.

Journal ArticleDOI
TL;DR: It is demonstrated that somatostatin in humans not only exerts an inhibitory effect on growth hormone secretion but also on TSH release in response to TRF, suggesting an interrelationship between the regulation of growth hormone and TSH secretion.
Abstract: Concomitant administration of somatostatin and thyrotropin-releasing factor (TRF) significantly inhibited the release of TSH induced by TRF without affecting the simultaneous secretion of prolactin (PRL) in normal adult subjects. However, within our experimental design (iv bolus of 250 μg TRF plus 500 μg somatostatin followed by constant infusion of 500 μg somatostatin over 45 min) the inhibition of TSH release by somatostatin was incomplete. The present study demonstrates that somatostatin in humans not only exerts an inhibitory effect on growth hormone secretion but also on TSH release in response to TRF. These findings suggest an interrelationship between the regulation of growth hormone and TSH secretion.

Journal ArticleDOI
TL;DR: Data indicate that a positive feedback relationship between estrogen and PRL release exists in humans, and the corresponding serum luteinizing hormone and follicle-stimulating hormone fell progressively during the study period.
Abstract: The effect of estrogen on prolactin (PRL) release and gonadotropin suppression was assessed in six experiments performed on four hypogonadal women. Ethinyl estradiol at a dose of 1 microgram/kg per day induced a significant elevation of serum PRL levels within the 1st wk of treatment. There was a further rise until a plateau was reached in about 3-4 wk to levels of more than 3 times the initial concentration. This was accompanied by a pattern of increased episodic fluctuation. The corresponding serum luteinizing hormone and follicle-stimulating hormone fell progressively during the study period. These data indicate that a positive feedback relationship between estrogen and PRL release exists in humans.

Journal ArticleDOI
TL;DR: Serum LH, FSH, prolactin and progesterone were determined in male and female prepuberal rats and all hormones were increased during the peripuberal period with cyclic fl...
Abstract: Serum LH, FSH, prolactin and progesterone were determined in male and female prepuberal rats. Neonates of both sexes had high LH and FSH levels, the values in the females being higher than those in the males. Serum prolactin and progesterone were low in neonatal rats. A curious LH secretion pattern occurred in female rats between days 10 and 20; high LH levels were observed in 10–15‰ of the rats during this time, whereas the male rats showed only minor fluctuations. At the same time serum FSH was elevated in both sexes. Again, the values in the females were higher than in the males. Serum prolactin was still low, whereas progesterone rose slightly in both sexes. Serum LH and FSH remained low between days 21 and the immediate peripuberal period (i.e., days 37–45) in males and females, and serum prolactin rose steadily during this period. Progesterone also increased following the prolactin pattern. All hormones (LH, FSH, prolactin and progesterone) were increased during the peripuberal period with cyclic fl...

Journal ArticleDOI
TL;DR: Intact rats were injected once, subcutaneously, with either 1.0 mg of ergocornine, free base (ECO), to prevent prolactin release, or an equine antiserum to bovine LH (LH-AS), to neutralize endogenous LH, on one of the days between days 6 and 12 of pregnancy.
Abstract: Intact rats were injected once, subcutaneously, with either 1.0 mg of ergocornine, free base (ECO), to prevent prolactin release, or an equine antiserum to bovine LH (LH-AS), to neutralize endogenous LH, on one of the days between days 6 and 12 of pregnancy. ECO treatment was uniformly abortifacient on day 6, only slightly less so on day 7, and was ineffective at 0400 hr or later on day 8. LH-AS treatment on day 6 or 7 induced abortion in very few rats; at 0400 hr on day 8, it induced abortion in 92%, and at 1200 or 1600 hr on day 8 or at 1200 hr on day 10, in 100% of the rats; when given on day 12, it was again ineffective. ECO did not depress serum LH or FSH levels, but abolished the nocturnal surge of prolactin; ECOinduced abortions could be prevented by treatment with prolactin but not with LH. Absorption of the LH-AS with LH, but not with either FSH or bovine serum abolished its abortifacient effect. A severe fall in the serum progesterone level occurred within 12 to 48 hr after treatment with either...

Journal ArticleDOI
TL;DR: “Big” prolactin constituted 8–20% of the total immunoreactivity in plasma samples from normal subjects, patients with chromophobe adenomas, and idiopathic galactorrhea, while the highest amounts of “big” Prolactin were seen in plasmas from pregnant subjects.
Abstract: Two discrete components of circulating human prolactin have been identified by immunoassay after gel filtration of Sephadex G-100 in all plasma samples so far examined. The major peak, termed “little” prolactin, eluted coincident with purified 131I-prolactin. The less retarded second peak, termed “big” prolactin, emerged between human serum albumin and ovalbumin. “Big” and “little” prolactin fractions were indistinguishable immunologically when assayed at multiple dilutions. “Big” prolactin constituted 8–20% of the total immunoreactivity in plasma samples from normal subjects, patients with chromophobe adenomas, and idiopathic galactorrhea. Neither TRH stimulation nor l-dopa suppression produced major changes in the plasma ratios of “big” to “little” prolactin, which were similar in normals and tumor patients. The highest amounts of “big” prolactin (range 16–31%) were seen in plasmas from pregnant subjects. Both components also appear to be present in pituitary extracts and pituitary culture medi...

Journal ArticleDOI
TL;DR: It is suggested that it is feasible to utilize the soluble receptor for the development of a very sensitive radioreceptor assay for prolactin and, further, to obtain a highly purified receptor in sufficient quantity to facilitate studies on its physiological, biochemical, and immunological properties.

Journal ArticleDOI
TL;DR: The results demonstrate the existence of an apparently unique kind of neuroendocrine reflex, copulation-induced, which results in rickets in the absence of the ovaries and abolish immediately both surges.
Abstract: Cervical stimulation in the rat institutes a pattern of prolactin secretion consisting of two daily surges, one diurnal and one nocturnal, which continue for the greater part of pseudopregnancy. This contrasts with the diestrous day 1–2 interval of the estrous cycle wherein prolactin levels are low and relatively unchanging. A variety of noxious procedures such as aortic cannulation and serial blood sampling, sham ovariectomy and sham surgical cuts in the hypothalamus selectively and temporarily suppresses the diurnal prolactin surges of pseudopregnancy; the nocturnal surges remained unaffected. In the absence of the ovaries (removed on day 0 of pseudopregnancy) the diurnal prolactin surges have disappeared no later than day 5, whereas the nocturnal surges are present at day 6 but have disappeared by day 10. Hypothalamic retrochiasmatic cuts abolish immediately both surges. These results demonstrate the existence of an apparently unique kind of neuroendocrine reflex, copulation-induced, which results in r...

Journal ArticleDOI
TL;DR: Serum LH levels were virtually constant throughout the estrous cycle, except for the preovulatory surge between 1300 hr and 1900 hr on Day 4 with a peak level at 1600 hr, and in marked contrast to these changes in serum levels of FSH.
Abstract: Follicle-stimulating hormone (FSH), luteinizing hormone (LH) and prolactin concentrations were determined by radioimmunoassay (NIAMD-Rat RIA) of sera from intact hamsters, which were decapitated at selected times during the 4-day estrous cycle. Serum FSH concentrations on Day 1 of the cycle (day of ovulation) were 2- to 6-fold greater than the levels on Day 2 and 5 to 12-fold greater than the mean, “basal,” level of FSH (53 ± 2 ng/ml; 80 hamsters) found during Day 3 and until 1200 hr, Day 4. There was a biphasic serum FSH pattern on Day 4 (proestrus) which was demarcated by the initiation of the preovulatory surge at 1400 hr, the peak level at 1600 hr, the decay of the surge by 2100 hr, and the subsequent elevation to the high levels present on Day 1. In marked contrast to these changes in serum levels of FSH, LH levels were virtually constant throughout the estrous cycle, except for the preovulatory surge between 1300 hr and 1900 hr on Day 4 with a peak level at 1600 hr. Prolactin concentrations varied a...

Journal ArticleDOI
TL;DR: In five patients with acromegaly, the chronic hypersecretion of growth hormone was effectively inhibited by the administration of synthetic somatostatin, which induced a concomitant fall in circulating levels of insulin, glucose and prolactin and an increase in fatty free acids.
Abstract: In five patients with acromegaly, the chronic hypersecretion of growth hormone was effectively inhibited by the administration of synthetic somatostatin (intravenous bolus of 250 μg followed by a constant infusion, 500 μg per 45 minutes). The rate of growth hormone decline during the infusion was rapid, with a mean half-time of 24 minutes. After the infusion, a return of secretion to previously elevated levels was observed. These data suggest that the inhibitory action of somatostatin on growth hormone secretion is nearly complete and that the biologic action of somatostatin is brief. In addition, somatostatin induced a concomitant fall in circulating levels of insulin, glucose and prolactin and an increase in fatty free acids. No effect on levels of thyrotropin, follicle-stimulating hormone or luteinizing hormone was observed. (N Engl J Med 290:935–938, 1974)

Journal ArticleDOI
TL;DR: Estrone administration to male rats induced a 10- to 30-fold increase in specific binding of ovine prolactin and human growth hormone after 8-12 days with a significant increase first seen after 4 but not 2 days of injection, demonstrating estrogen induction of a lactogenic receptor.
Abstract: A receptor exists in female rat liver with high specificity for lactogenic hormones. Previous work showed the receptor level increased at the time of puberty in female but not male animals. Pregnancy caused a further substantial increase. Here we show that estrone (50 μg/day) administration to male rats induced a 10- to 30-fold increase in specific binding of ovine prolactin and human growth hormone after 8-12 days with a significant increase first seen after 4 but not 2 days of injection. In females, this regimen increased binding to pregnancy levels. In prepuberal (20-days-old) male and female rats, estrone was also markedly stimulatory. The binding sites for ovine prolactin and human growth hormone were of high affinity in liver membranes from both female and estrone-treated male rats (Ka = 0.6 to 1.4 × 109 M-1). Estrone and estradiol were equally effective in inducing the lactogenic receptor. Estriol (50 μg/day), progesterone (500 μg/day), human placental lactogen (1 mg/day), and testosterone (100 μg/day) were without influence. Hypophysectomy drastically decreased the levels of lactogenic receptor in mature female rats, and estrogen treatment failed to restore receptor levels to normal. Hypophysectomized male rats were also unresponsive to estrogen. Throughout these studies the specific binding of 125I-labeled insulin remained relatively constant. This work demonstrates estrogen induction of a lactogenic receptor. The pituitary gland appears to have a critical, though presently undefined, role in the induction process.

Journal ArticleDOI
TL;DR: Nine female patients with galactorrhea selected for treatment with Bromocriptin (CB-154), a specific inhibitor of prolactin secretion induced a fall in serum hPRL accompanied by cessation of milk secretion in 8 patients, indicating a suprasellar cause for the patients' failure to cycle.
Abstract: Nine female patients with galactorrhea were selected for treatment with Bromocriptin® (CB-154), a specific inhibitor of prolactin secretion. Elevated plasma prolactin (hPRL) was found in 7 of these cases, whereas 2 exhibited values within normal limits. LHRH (100 μg) stimulation elicited plasma LH/FSH increases in 6 of the women who were amenorrheic prior to therapy, indicating a suprasellar cause for the patients' failure to cycle. After TRH (250 μg) stimulation, 5 women out of 6 exhibited a blunted hPRL response and 4 of them failed to show any elevations after administration of chlorpromazine. It was only in one patient who exhibited basal hPRL within the normal range, that an average response to TRH was elicited. The possible mechanisms explaining the low levels of pituitary stimulation obtained are discussed. Treatment with CB-154 (3–5 mg/day) induced a fall in serum hPRL accompanied by cessation of milk secretion in 8 patients. Menses were restored in 7 amenorrheic women and corpora lutea f...

Journal ArticleDOI
TL;DR: To establish a functional classification of pituitary tumors, immunoperoxidase stains specific for hGH and prolactin were applied to 21 surgically removed tumors from patients whose plasma levels of the two hormones had been determined preoperatively by radioimmunoassay.
Abstract: Excess secretion of growth hormone (hGH) and prolactin by some pituitary tumors has been associated with adenomas classified by tinctorial stains as acidophilic, mixed acidophilic-chromophobe, and chromophobe. In order to establish a functional classification of such tumors, immunoperoxidase stains specific for hGH and prolactin were applied to 21 surgically removed tumors from patients whose plasma levels of the two hormones had been determined preoperatively by radioimmunoassay. Five normal pituitary glands obtained at autopsy were also studied by immunoperoxidase technique. Eight patients had acromegaly and elevated plasma hGH; in 7 of these, hGH was located in the tumor cells by immunoperoxidase. Twelve patients had hyperprolactinemia; the immunoenzyme method identified prolactin in 10 of their tumors. Four patients with tumor prolactin were also acromegalic with demonstrable tumor hGH. Tumor hGH was found in 1 patient with normal plasma hGH, and tumor prolactin in 1 patient with normal plasm...

Journal ArticleDOI
TL;DR: The data indicate that patients with hyperprolactinemia encompassing a varied etiological range frequently show loss of the normal sleep-associated increase in prolactin secretion as well as abnormalities in the regulation of the other hypothalamic pituitary-regulated hormones.
Abstract: Prolactin secretion in normal adults is characterized by periods of episodic secretion which increase in magnitude during sleep. In this study, we report the 24-h mean prolactin concentrations, prolactin secretory patterns, and associated pituitary hormone function in nine patients (seven women and two men) with hyperprolactinemia of diverse etiologies. Four of the women and one of the men had clinically demonstrable pituitary tumors, one boy had a hypothalamic tumor, and the three other women had "functional" hyperprolactinemia. The 24-h mean prolactin concentrations derived from averaging the 20-min interval samples for 24 h ranged from 28.6 to 1,220 ng/ml. The plasma prolactin patterns in these patients showed persistence of episodic secretion in all and loss of the normal sleep-wake difference in plasma prolactin in seven of nine. Three of the patients with galactorrhea and comparable 24-h mean prolactin concentrations (58.3, 59.7, and 64.3 ng/ml) showed similar prolactin secretory patterns despite different etiologic mechanisms. Evaluation of the secretory patterns of luteinizing hormone (LH) in these patients showed loss of normal pulsatile LH release and a low 24-h mean LH concentration in the patient with the pituitary tumor, while the two patients without clinically demonstrable pituitary tumors ("post-pill" galactorrhea and "idiopathic" galactorrhea) showed normal LH secretory patterns and 24-h mean LH concentrations. The 24-h mean cortisol concentrations and secretory patterns were normal in five of the seven patients who had these parameters measured. The patient with the hypothalamic tumor had a low 24-h mean cortisol concentration and production rate and absent response to metyrapone. The patient with "idiopathic" galactorrhea had an elevated 24-h mean cortisol concentration but normal cortisol production rate and urinary 17-hydroxycorticoid excretion. Growth hormone secretion was abnormal in four of the patients (one with the hypothalamic tumor and three with pituitary tumors). Thyrotropin-releasing hormone (TRH) administration in four patients resulted in normal TSH release in two patients (one of whom developed galactorrhea after the test), an absent response in the patient with the hypothalamic tumor, and a blunted response in one of the women with a pituitary tumor. The two men had low 24-h mean plasma testosterone concentrations (69 and 30 ng/100 ml) and symptoms of impotence and loss of libido. Five of the women (four with pituitary tumors and one with Chiari-Frommel syndrome) had either low 24-h mean LH concentrations, abnormal LH secretory patterns, or both. These data indicate that patients with hyperprolactinemia encompassing a varied etiological range frequently show loss of the normal sleep-associated increase in prolactin secretion as well as abnormalities in the regulation of the other hypothalamic pituitary-regulated hormones. The finding that the abnormalities in LH, growth hormone, thyrotropin, and cortisol (adrenocorticotrophic) secretion were almost uniformly confined to the patients with the clinically demonstrable hypothalamic or pituitary tumors suggests that the size of the lesion is the critical factor.

Journal ArticleDOI
TL;DR: PIF activity of this preparation and catecholamines were examined in vivo and it was found that a purified porcine hypothalamic preparation with high PIF activity as tested by an in vivtro assay was found to contain a high content of catechols.
Abstract: Since a purified porcine hypothalamic preparation with high PIF activity as tested by an in vivtro assay was found to contain a high content of catecholamines, PIF activity of this preparation and catecholamines were examined in vivo. The test samples were infused for 30 min into a hypophysial portal vessel of male rats anesthetized with urethane. Infusion of 30 ng and 300 ng of porcine PIF preparation in 5% glucose solution decreased serum prolactin levels significantly, as compared to the respective preinfusion levels. Infusion of 60 ng and 600 ng, but not 6 ng, of dopamine hydrochloride in glucose solution caused a significant reduction in prolactin levels. Administration of 6 ng, 60 ng, and 600 ng of norepinephrine bitartrate in 5% glucose also decreased serum prolactin levels. The magnitude of decrease in prolactin levels appeared to be dose-related. When dopamine hydrochloride (600 ng) and norepinephrine bitartrate (600 ng) were dissolved in 0.9% saline and infused into the rat, their PIF activity w...


Journal ArticleDOI
27 Sep 1974-Science
TL;DR: The results suggest that melatonin is not the pineal antigonadotrophic factor in the male golden hamster and that pituitary levels of prolactin return to normal after pinealectomy and melatonin treatment.
Abstract: Exposure of male hamsters to short daily photoperiods (1 hour of light and 23 hours of darkness daily for 9 weeks led to total involution of the testes and accessory sex organs (seminal vesicles and coagulating glands). Pituitary levels of immunoreactive prolaction also decreased by about 60 percent after dark exposure. The inhibitory effects of darkness on the reproductive organs were prevented either by pinealectomy or by the subcutaneous implantation of a melatonin-beeswax pellet into the animals each week. Both pinealectomy and melatonin treatment also returned pituitary levels of prolactin toward normal. The results suggest that melatonin is not the pineal antigonadotrophic factor in the male golden hamster.

Journal ArticleDOI
TL;DR: Fifteen female psychiatric patients developed inappropriate breast activity and/or amenorrhoea while receiving treatment with phenothiazines and related drugs and withdrawal of medication led to a resumption of menstruation with a normal cycle pattern of LH, oestrogens and progesterone.
Abstract: Fifteen female psychiatric patients developed inappropriate breast activity and/or amenorrhoea while receiving treatment with phenothiazines and related drugs. In the majority plasma prolactin was clearly elevated. In those whose menstruation had not been affected, circulating levels of luteinizing hormone (LH), immunoreactive oestrogens (oestradiol) and progesterone followed the normal pattern of the menstrual cycle. In amenorrhoeic subjects, basal LH values were variable, mid-cycle peaks were absent, and oestrogen and progesterone levels were similar to values reported during the follicular phase of a normal cycle. Medication was withdrawn subsequently from four patients. Breast secretion diminished and plasma prolactin fell to within the normal range, rising again when the drugs were reinstated. In two of three amenorrhoeic patients, withdrawal of medication led to a resumption of menstruation with a normal cyclical pattern of LH, oestrogens and progesterone.

Journal ArticleDOI
15 Nov 1974-Nature
TL;DR: Bovine STH and bovine prolactin were labelled with 125I and their binding to lymphoid cells was studied and it was assumed that STH binds to the thymocytes and thereby changes their physiological activity.
Abstract: As well as its general trophic effect on lymphoid tissue1, growth hormone (STH) specifically increases the activity of thymocytes in a graft versus host reaction2 and their helper activity3 In vitro studies showed that STH alters the mitotic activity, RNA and protein metabolism of thymocytes4,5 At least for the effects obtained in vitro, it is assumed that STH binds to the thymocytes and thereby changes their physiological activity The nature of this binding has not been studied To learn about the characteristics of the surmised interaction, bovine STH (Nutritional Biochemicals, Cleveland, Ohio) and bovine prolactin (National Institutes of Health, lot NIH B4) were labelled with 125I and their binding to lymphoid cells was studied

Journal ArticleDOI
TL;DR: It is concluded that prolactin and corticosterone both respond to identical stimuli but that the Prolactin response shows different characteristics from the adrenal response suggesting that different regulatory mechanisms are involved.
Abstract: &NA; Temporal characteristics of hormonal responses to handling and novel environment were studied in the rat in order to determine whether the same factors which modify corticosterone responses, i.e., time of day and type of stimulus, also modify prolactin and GH responses. Resting corticosterone showed the expected difference between crest and trough of the diurnal cycle. In contrast, GH and prolactin showed no difference at these times. Prolactin elevation occurred in response to the same stimuli which produced adrenal activation. Prolactin responses, however, differed from adrenal responses in being more rapid at the trough of the adrenal cycle and slower at the crest. In contrast to prolactin and corticosterone, GH showed a drop (nonsignificant) following stimulation. It is concluded that prolactin and corticosterone both respond to identical stimuli but that the prolactin response shows different characteristics from the adrenal response suggesting that different regulatory mechanisms are involved.