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,.

Persistent Changes in Gene Expression Induced by Estrogen and Progesterone in the Rat Mammary Gland

Abstract: Epidemiological studies have consistently shown that an early full-term pregnancy is protective against breast cancer. We hypothesize that the hormonal milieu that is present during pregnancy results in persistent changes in the pattern of gene expression in the mammary gland, leading to permanent changes in cell fate that determine the subsequent proliferative response of the gland. To investigate this hypothesis, we have used suppression subtractive hybridization to identify genes that are persistently up-regulated in the glands of E- and progesterone (P)-treated Wistar-Furth rats 28 d after steroid hormone treatment compared with age-matched virgins. Using this approach, a number of genes displaying persistent altered expression in response to previous treatment with E and P were identified. Two markers have been characterized in greater detail: RbAp46 and a novel gene that specifies a noncoding RNA (designated G.B7). Both were persistently up-regulated in the lobules of the regressed gland and required previous treatment with both E and P for maximal persistent expression. RbAp46 has been implicated in a number of complexes involving chromatin remodeling, suggesting a mechanism whereby epigenetic factors responsible for persistent changes in gene expression may be related to the determination of cell fate. These results provide the first support at the molecular level for the hypothesis that hormone-induced persistent changes in gene expression are present in the involuted mammary gland.

Mechanisms of physical and emotional stress

Abstract: The Concept of Stress and Its Historical Development.- Basic Mechanisms of the Stress Response.- Sympathoadrenal Medullary System and Stress.- Behavioral Pharmacology of Stress: Focus on CNS Corticotropin-Releasing Factor.- Glucocorticoid Receptors and Behavior: Implications for the Stress Response.- CRH Effects on Central Noradrenergic Neurons: Relationship to Stress.- Hypophysiotropic Regulation of Stress-Induced ACTH Secretion.- Corticotropin Releasing Factor Receptors: Characterization and Actions in the Anterior Pituitary Gland.- Regulation of Pituitary Cyclic AMP, Plasma Prolactin and POMC-Derived Peptide Responses to Stressful Conditions.- Corticotropin-Releasing Hormone Receptors in Brain.- Studies on the Secretion of Corticotropin-Releasing Factor into Hypophysial Portal Blood.- Is There a "Final Common Pathway" in the Regulation of ACTH Release?.- Regulation of Vasopressin and Oxytocin Release In Vitro.- Regulation of Rat Hypothalamic Corticotropin-Releasing Hormone Secretion In Vitro Potential Clinical Implications.- Is the Benzodiazepine/GABA Receptor Chloride Ionophore Complex Involved in Physical and Emotional Stress?.- Stress and Immunity.- Corticosteroids and the Immume Response.- Lipocortins.- Immunologically-Mediated Pituitary-Adrenal Activation.- Glucocorticoid Antagonists and the Role of Glococorticoids at the Resting and Stress State.- Psychological Influences on Immunity: Making Sense of the Relationship between Stressful Life Events and Health.- Physical Stress.- Endocrine Response to Multiple Sensory Imput Related to Injury.- Hormonal Responses to Surgical Stress.- Hormonal Responses to the Stress of Exercise.- Stress, Development and Reproduction.- Stress in the Fetus and Newborn.- Maternal Modulation of Pituitary-Adrenal Activity During Ontogeny.- Maternal Alcohol Consumption and Stress Responsiveness in Offspring.- Temperamental Influence on Reactions to Unfamiliarity and Challenge.- Physiological and Behavioral Aspects of Stress in Adolescence.- Prolactin and Growth Hormone Secretion in Stress.- Stress and Reproduction: Physiologic and Pathophysiologic Interactions between the Stress and Reproductive Axes.- Human Placenta and the Hypothalamic-Pituitary-Adrenal Axis.- Individual Differences and Stress Response: Studies of a Wild Primate.- Psychological and Somatic Factors in Women with Pain Due to Pelvic Congestion.- Emotional Stress and Psychiatric Illness.- Neurochemical and Electrophysiological Events Underlying Stress-Depression in an Animal Model.- Implications of Behavioral Sensitization and Kindling for Stress-Induced Behavioral Change.- Effects of Psychological Stress on Pituitary Hormones in Man.- Preclinical and Clinical Evidence for the Involvement of Corticotropin-Releasing Factor in the Pathogenesis of Depression.- The Psychology of Stress: Run Silent, Run Deep.- The Clinical Implications of Corticotropin-Releasing Hormone.

Endocrine and reproductive dysfunction following fractionated total body irradiation in adults.

Abstract: The endocrine and reproductive sequelae of total body irradiation for haematological malignancy have been studied in 21 patients (11 male) who were treated with 10 Gy in five fractions or 12 or 13.2 Gy in six fractions over 3 days. Eighteen patients (eight male) aged 16-49 years underwent dynamic tests of the hypothalamic-pituitary axis with insulin hypoglycaemia, thyrotrophin releasing hormone (TRH) and gonadotrophin releasing hormone stimulation and basal measurement of prolactin, sex steroids and thyroid hormones. Growth hormone responses (mean peak 64 +/- 36 mU/l, range 21-146 mU/l) and cortisol responses (mean peak 831 +/- 122 nmol/l, range 626-1105 nmol/l) were all within the normal range. Two patients had minimally elevated serum prolactin levels (445 and 588 mU/l, normal less than 350 mU/l). Serum thyroxine levels (57-133 nmol/l) were normal but six patients had elevated basal thyrotrophin (TSH) levels (6-9 mU/l) and seven had an exaggerated TSH response to thyrotrophin releasing hormone, indicating radiation-induced damage to the thyroid. Amenorrhea developed within 3 months of irradiation in all females and oestradiol levels were low, at 37-108 pmol/l (mean 58 +/- 22 pmol/l). Severe oligospermia or azoospermia was noted in men tested 5-70 months after irradiation and testicular volume was below the normal adult range in five of seven men assessed. Serum testosterone levels (12.4-35 nmol/l) were normal. Gonadotrophin-releasing hormone-stimulated gonadotrophin levels were elevated in all patients. However, two men have fathered two children each; one has refused semen analysis, but the other has a sperm count of 7 x 10(6)/ml (60 per cent motile, 20 per cent abnormal forms) 70 months after irradiation. When given by the above fractionated regimens, the endocrine sequelae of total body irradiation are limited to gonadal failure requiring oestrogen replacement in women and severe impairment of fertility in men. Subclinical thyroid dysfunction has been seen in 39 per cent of patients there is no evidence of direct damage to the hypothalamic pituitary axis.

Functional Evaluation of Prolactin Secretion in Patients with Hypothalamic-Pituitary Disorders

Abstract: Prolactin secretion was assessed in 23 patients with hypothalamic-pituitary disorders using L-Dopa suppression, chlorpromazine (CPZ), and thyrotropin-releasing hormone (TRH) stimulation tests. Based on the responses to these tests, three groups of patients were identified: those with panhypopituitarism (group I) and those with partial hypopituitarism either with (group II) or without (group III) evidence of hypothalamic involvement. Panhypopituitary patients (group I) consistently had low serum prolactin values and failed to respond to all tests. Patients with hypothalamic involvement (group II) exhibited (a) elevated basal prolactin values. (b) an increase in serum prolactin after TRH stimulation. (c) blunted response to L-Dopa, and (d) lack of response to chlorpromazine stimulation. Patients with partial hypopituitarism but without hypothalamic involvement (group III) had normal serum prolactin levels and suppressed normally after L-Dopa; although the magnitude of response to both stimulatory agents was significantly lower than normally found the ratio of prolactin levels post-CPZ and TRH (Δ prolactin CPZ/Δ prolactin TRH) was similar to the ratio of normal individuals suggesting that these patients (group III) had a normal hypothalamic-pituitary prolactin axis. In the 23 patients studied, the most consistent disorder of pituitary function proved to be an abnormal response to one or other of the three tests employed for the evaluation of prolactin secretion. Hence these tests have considerable potential as a sensitive screening procedure in the evaluation of patients suspected of having hypothalamic-pituitary disease.

Effects of Morphine and Naloxone on Serum Levels of Luteinizing Hormone and Prolactin in Prepubertal Male and Female Rats

Abstract: The effects of morphine (M) and naloxone (N) on serum levels of luteinizing hormone (LH) and prolactin (PRL) in prepubertal male and female rats were investigated. N raised serum LH concentrations in female rats at 10, 15, 20, 25 and 30 days of age, but increased serum LH levels in male prepubertal rats only at 30 days of age. M significantly depressed serum LH values in both sexes only at 15 days of age. M increased serum PRL levels in immature rats of both sexes in all age groups, except in 25-day-old males, whereas N decreased serum PRL only in 25-day-old male rats. These data show that there are differences in the pituitary LH and PRL responses to M or N of immature as compared to the responses previously reported in mature rats, and suggest that the endogenous opioid peptides may have a role in regulating LH and PRL secretion in immature rats.