Topic
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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TL;DR: The results underlie the significant effects that obesity has on circadian organization of hormone secretion and individual plasma glucose values correlating with circulating corticosterone in high-fat fed rats only are analyzed.
Abstract: Circadian rhythmicity is affected in obese subjects. This article analyzes the effect of a high-fat diet (35% fat) on 24-h changes circulating prolactin, luteinizing hormone (LH), testosterone, corticosterone, thyroid-stimulating hormone (TSH) and glucose, and pineal melatonin content, in rats. When body weight of rats reached the values of morbid obesity, the animals were sacrificed at six different time intervals throughout a 24-h cycle, together with age-matched controls fed a normal diet (4% fat). Plasma hormone levels were measured by specific radioimmunoassays and glucose concentration by an automated glucose oxidase method. In rats under a high-fat diet, a significant disruption of the 24-h pattern of plasma TSH, LH, and testosterone and a slight disruption of prolactin rhythm were found. Additionally, high-fat fed rats showed significantly lower total values of plasma TSH and testosterone and absence of correlation between testosterone and circulating LH levels. Plasma corticosterone levels increased significantly in high-fat fed rats and their 24-h variation became blunted. In obese animals, a significant hyperglycemia developed, individual plasma glucose values correlating with circulating corticosterone in high-fat fed rats only. The amplitude of the nocturnal pineal melatonin peak decreased significantly in high-fat fed rats. The results underlie the significant effects that obesity has on circadian organization of hormone secretion.
115 citations
TL;DR: Data indicate that two steroid hormones, hydrocortisone and progesterone, were able to modulate the prolactin-induced accumulation of casein mRNA, whereas progester one is able to prevent casein RNA accumulation.
115 citations
TL;DR: It is found that the levels of prolactin and growth hormone mRNAs to remain nearly constant during mid-to-late gestation.
115 citations
TL;DR: There is insufficient evidence to recommend this drug as primary therapy for either prolactin-secreting or nonfunctional macroadenomas, but the drug may have potential as a preoperative adjunct to effect shrinkage of prolACTinomas and theoretically, at least, make excision easier and possibly more complete.
Abstract: ✓ Bromocriptine inhibits prolactin secretion and causes size reduction of prolactin-secreting adenomas. The effect of the drug upon pituitary tumors other than prolactinomas is uncertain. The authors report a prospective series of 12 patients with pituitary macroadenomas in whom bromocriptine was administered for 6 weeks prior to transsphenoidal surgery. Five of the patients had computerized tomographic documentation of significant reductions in tumor size (Group A) and six had no change (Group B) during 3 and 6 weeks of bromocriptine administration. One patient who demonstrated size reduction in his tumor was not assigned to either group as he was treated with high-dose dexamethasone concurrently with the bromocriptine. Pathological examination (light and electron microscopy and immunocytochemistry) indicated that all Group A patients harbored tumors with prolactin granules whereas all Group B tumors lacked such granules. Adenoma cells in the responsive tumors were involuted with reduced cytoplasmic, nuc...
115 citations
Journal Article•
TL;DR: It is concluded that insulin administered in vivo appears to display intrinsic growth-stimulating properties on the mammary tumor tissue, similar to those previously demonstrated in organ culture.
Abstract: Summary Administration of insulin for 6 weeks at a daily dose of 2.5 i.u./100 g body weight, together with a 10% glucose solution as drinking fluid, increased tumor growth 8.3-fold as compared with a matched, untreated control group. Administration of insulin alone or of a 10% glucose solution alone produced a smaller yet statistically significant increase (4.8- and 2.2-fold, respectively). In oophorectomized rats, administration of the same dose of insulin, together with the 10% glucose solution for 4 weeks, failed to prevent tumor regression resulting from oophorectomy. On the other hand, in hypophysectomized rats, administration of insulin for 3 weeks at a daily dose of 0.4 to 0.8 i.u./100 g body weight significantly reactivated tumor growth, as compared with a matched control group, when started 21 days after hypophysectomy. Both insulin-treated and control groups received, in addition, a 10% glucose solution and daily s.c. injections of 1.5 mg ovine prolactin; the latter proved by itself incapable of significantly reactivating tumor growth. It is concluded that insulin administered in vivo appears to display intrinsic growth-stimulating properties on the mammary tumor tissue, similar to those previously demonstrated in organ culture. The present study, complementing earlier investigations in alloxan-diabetic rats, provides further evidence suggesting that the rat mammary carcinoma, in addition to being estrogen and prolactin dependent, is also insulin dependent.
115 citations