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,.

Puberty in girls: correlation of serum levels of gonadotropins, prolactin, androgens, estrogens, and progestins with physical changes.

Abstract: Twenty-seven girls aged 8 to 18 were studied in a longitudinal prospective fashion. Serum samples were collected at 6 month intervals up to 4 years and radioassayed for hormones of pituitary, ovarian, and adrenal origin. A progressive elevation of luteinizing hormone (LH), follicle-stimulating hormone/FSH), estradiol (E2), dehydroepiandrosterone (DHA), and androstenedione (delta4) occurred during puberty and continued until menarche. The onset of puberty occurred concomitantly with an elevation of estrone (E1) dehydroepiandrosterone (DHA), dehydroepiandrosterone sulfate (DHAS), and 17-hydroxyprogesterone (17-OH-P). Prolactin (Prol) and progesterone (Prog) concentrations did not change during puberty until after menarche. After menarche, levels of LH and FSH were comparable with menstruating adult females. Concentrations of E2 and Prog were lower during the second half of the cycle among most regularly menstruating subjects than expected during the luteal phase. LH and Prog levels indirectly suggest that ovulation occurs in a few girls within months after menarche.

Loss of Central Nervous System Component of Dopaminergic Inhibition of Prolactin Secretion in Patients with Prolactin-Secreting Pituitary Tumors

Abstract: A B S T RA C T The administration of L-dopa suppresses prolactin (PRL) secretion in normal subjects and in patients with hyperprolactinemia, although it is not known whether this effect, which requires the conversion of dopa to dopamine, is mediated peripherally or through the central nervous system. To distinguish between these effects, 10 normal subjects (6 male, 4 female) and 8 patients with hyperprolactinemia associated with pituitary tumors were given L-dopa, 0.5 g alone, or 0.1 g after a 24-h pretreatment with carbidopa, 50 mg every 6 h, which produces peripheral dopa decarboxylase inhibition. Similar degrees of PRL suppression were observed in normal subjects (basal plasma PRL 13+2 ng/ml) after L-dopa alone (48±+4%) and after L-dopa plus carbidopa (58+6%). In patients with pituitary tumors and elevated plasma PRL (73+14 ng/ml), L-dopa alone led to PRL suppression comparable with that in normal subjects (47±+6%). However, L-dopa plus carbidopa resulted in only minimal suppression of plasma PRL (19+4%) which was significantly less than after L-dopa alone (P <0.001). Urinary homovanillic acid excretion, which reflected peripheral dopa decarboxylation was similar in controls and tumor patients after L-dopa both alone and after carbidopa pretreatment. Comparable suppression ofPRL levels in response to a dopamine infusion (4 jig/kg per min for 3 h) was observed in controls and tumor patients. The results indicate that although peripheral conversion of exogenous dopa to dopamine can suppress PRL secretion, in normals, the central nervous system conversion ofdopa to dopamine in the presence of peripheral dopa decarboxylase inhibition is sufficient to account for its PRL-suppressive effects. In contrast, patients This work was presented in part at the AFCR National

Circadian Periodicity of Serum Prolactin Concentration in Man

Abstract: Immunoreactive human serum prolactin of pituitary origin has been measured by a radioimmunoassay developed for ovine prolactin. Blood samples were collected at four-hour intervals during a 24-hour period from 12 non-pregnant women, three pregnant women, and seven adult men. A circadian periodicity was found in serum prolactin concentration, with peak values during the night, between 1 a.m. and 5 a.m. for the non-pregnant women, and at 5 a.m. for the adult men. Mean serum levels of prolactin were 1·5 times higher in non-pregnant women than in men. In women investigated during the last month of their pregnancy the mean serum prolactin levels were 2·3 times higher than in the non-pregnant women, but there was no circadian periodicity.