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Prolactin

About: Prolactin is a research topic. Over the lifetime, 22356 publications have been published within this topic receiving 609537 citations. The topic is also known as: lactotropin, & PRL,.


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Journal ArticleDOI
TL;DR: It is hypothesized that opiates and opioid peptides increase prolactin release by reducing the activity of the tuberoinfundibular dopaminergic system through interaction with catecholaminergic systems.
Abstract: The is evidence that some of the actions of both endogenous and exogenous opioids (e.g., stimulation of prolactin release) are mediated by interaction with catecholaminergic systems. Morphine (1.67, 5, and 15 mg/kg of body weight, intraperitoneally) altered dopamine turnover as measured by the alpha-methyl-p-tyrosine method in the median eminence, neostriatum, and frontal cortex of male Sprague-Dawley rats. The turnover rate of dopamine was reduced in the median eminence and frontal cortex but accelerated in the neostriatum. In the frontal cortex all doses were effective in decreasing dopamine turnover; however, in the median eminence the lowest dose of morphine did not significantly alter dopamine turnover. All three doses accelerated dopamine turnover in the neostriatum. Naloxone effectively reversed the effects of morphine at all doses in all brain areas, whereas it had no effect on turnover when given alone. In the median eminence, neostriatum, and frontal cortex, intraventricular injection of [D-Ala2,D-Leu5]-enkephalin (25 micrograms) or beta-endorphin (15 micrograms) produced the same effects on dopamine turnover as morphine. The actions of these peptides were blocked by naloxone. It is hypothesized that opiates and opioid peptides increase prolactin release by reducing the activity of the tuberoinfundibular dopaminergic system.

132 citations

Journal ArticleDOI
TL;DR: These studies assessed the effects of age on the ability of estradiol-17 beta (E2) to induce LH and PRL surges in ovariectomized young and middle-aged rats that previously had normal estrous cycles.
Abstract: These studies assessed the effects of age on the ability of estradiol-17β (E2) to induce LH and PRL surges in ovariectomized young and middle-aged rats that previously had normal estrous cycles. We determined whether any changes in the timing or amplitude of these surges could be correlated with changes in pituitary responsiveness to GnRH or with changes in norepinephrine (NE) and dopamine (DA) turnover rates in microdissected brain regions involved in cyclic gonadotropin release. Young (3–4 months old) and middle-aged (9–12 months old) rats were ovariectomized. One week later (day 0), they received Silastic capsules containing E2 which produced physiological serum concentrations of E2. Groups of rats were bled sequentially via indwelling right atrial cannulae 1–4 days after capsule implantation (days 1–4). All young rats displayed maximal LH surges by day 2 and exhibited equivalent surges on days 3 and 4. Middle-aged rats required the presence of E2 for at least 3 days before a maximal positive feedback ...

132 citations

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.

132 citations

Journal ArticleDOI
TL;DR: Sequence comparison revealed cod somatolactin to be similarly related to both GH and PRL, but slightly higher identity was observed to the tetrapod hormones than to the teleost hormones.
Abstract: The characterization of cod somatolactin (SL), a new pituitary protein belonging to the growth hormone/prolactin family, is described. Cod SL has a molecular weight of 26 kDa and consists of 209 amino acids, of which eight are Cys. The protein has three disulfide bonds between residues Cys5-Cys15, Cys65-Cys181, and Cys198-Cys206. The Cys residues at positions 42 and 180 are not involved in disulfide bonding. The positions of these disulfide bonds are homologous to those found in prolactin and growth hormone. Cod SL has two possible N-glycosylation sites, but only one appears to have carbohydrate units attached. Chemical analysis showed the following sugars to be present: galactose, mannose, N-acetylneuramic acid, and glucosamine. A smaller variant (23 kDa) of SL has been isolated, which is believed to be deglycosylated. Sequence comparison revealed cod SL to be similarly related to both GH and PRL, but slightly higher identity was observed to the tetrapod hormones (27-33%) than to the teleost hormones (21-27%).

131 citations

Journal ArticleDOI
TL;DR: Results of the current study suggest that GH and SL genes are also expressed in extrapituitary tissues even after the organogenesis of the pituitary gland, and suggest that these hormones may play important roles yet to be identified during embryonic development in fish.
Abstract: In fish, growth hormone (GH), prolactin (PRL) and somatolactin (SL) are three major peptide hormones produced in the pituitary gland. Using reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot analysis of the amplified products, the expression of GH, PRL, and SL genes were determined during the embryonic development in rainbow trout (Oncorhynchus mykiss). The mRNA for GH, PRL and SL were detected not only in embryos prior to or after organogenesis of the pituitary gland but also in mature oocytes as maternal messages. After hatching, all of these three mRNA species were detected at very high levels. Since the ontogenesis of the pituitary gland takes place on embryonic day (ED) 14, these observations suggest that the GH family protein genes are expressed in the developing embryos prior to the formation of the pituitary gland. Using the same RT-PCR assay, PRL mRNA was detected only in the head part of the fry whereas GH and SL mRNA were detected in both the head and trunk. In adult animals, though high levels of GH mRNA were primarily detected in the pituitary gland, brain, gill, and heart, low levels of GH mRNA were also detected in the kidney, liver, pyloric ceaca, and ovary. Results of the current study and those reported by Yang et al. (1997. Gen Comp Endocrinol 106:271-281) suggest that GH and SL genes are also expressed in extrapituitary tissues even after the organogenesis of the pituitary gland. Furthermore, these results suggest that these hormones may play important roles yet to be identified during embryonic development in fish.

131 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023360
2022585
2021202
2020221
2019180
2018172