+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Prolactin released in vitro from the pituitary of lactating, pregnant, and steroid-treated female or male rats stimulates prolactin secretion from pituitary lactotropes of male rats



Prolactin released in vitro from the pituitary of lactating, pregnant, and steroid-treated female or male rats stimulates prolactin secretion from pituitary lactotropes of male rats



Neuroendocrinology 91(1): 77-93



We have previously shown that soluble factor(s) in conditioned media (CM) from the central and peripheral regions of the anterior pituitary (AP) gland of lactating rats promoted the in vitro dose-related release of prolactin (PRL) from pituitary glands of male rats. In the present experiments we sought to determine whether CM from rats in different physiological states provoked similar effects (like those of lactating rats), and the nature of the factors, whether 23K PRL or other variants of the hormone, were responsible for these effects. Stimulatory effects were induced by CM from pregnant females and steroid-treated castrated males or females, but not from untreated castrated rats, intact males, or by a PRL standard. More potent effects occurred with CM from APs of early- than from mid- or late-lactating rats, and from rats unsuckled for 8 or 16 h than from those unsuckled for 32 h. With respect to the nature of factor(s) responsible for these effects, immunoprecipitation of PRL from the CM of lactating females and of steroid-treated, castrated males eliminated, whereas dephosphorylation or deglycosylation of CM of lactating rats greatly increased its effects upon PRL release. Also, electrophoretic analysis and Western blotting of the CM proteins under native and denaturing conditions revealed a variety of PRL variants, ranging from 14 to <90 kDa, in CM from lactating rats, and the main effects on PRL release were provoked by the 23- to 46-kDa PRL variants. These results indicate that specific effects upon male rat lactotropes may be exerted by PRL variants released from APs of lactating and non-lactating rats.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 055222822

Download citation: RISBibTeXText

PMID: 19590175

DOI: 10.1159/000228586


Related references

Age related release of prolactin by the pituitary and the pituitary hypothalamic complex in vitro an attempt to describe the development of the hypothalamic prolactin inhibiting and releasing activities in male rats. Journal of Endocrinology 115(3): 405-410, 1987

Age-related release of prolactin by the pituitary and the pituitary-hypothalamic complex in vitro: an attempt to describe the development of the hypothalamic prolactin-inhibiting and -releasing activities in male rats. Journal of Endocrinology 115(3): 405-409, 1987

The different effects of i.c.v. injection of pituitary adenylate cyclase activating polypeptide (PACAP) on prolactin secretion in adult male and lactating rats. Experimental Animals 58(5): 489-495, 2009

Anterior pituitary enzyme activities and prolactin secretion in male rats treated with psychotropic drugs. Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine 162(1): 191-193, 1979

Steroid modulation of prolactin release from single lactotropes in male and female rats studied by the reverse hemolytic plaque assay. Pharmacological Research Communications 20(12): 1075-1076, 1988

Effect of Amantadine on Prolactin Secretion, Pituitary Dna Synthesis and 3 H-Spiperone Binding in Male Estrogen-Treated Rats. Neuroendocrinology 51(6): 632-636, 2008

Effect of amantadine on prolactin secretion, pituitary DNA synthesis and 3H-spiperone binding in male estrogen-treated rats. Neuroendocrinology 51(6): 632-636, 1990

Prolactin message in brain and pituitary of adult male rats is identical: PCR cloning and sequencing of hypothalamic prolactin cDNA from intact and hypophysectomized adult male rats. Endocrinology 131(5): 2488-2490, 1992

Serum and pituitary prolactin, LH, and FSH in androgenized female and normal male rats treated with various doses of estradiol benzoate. Neuroendocrinology 11(1): 46-56, 1973

Effects of morphine on the serum prolactin levels of morphine tolerant and nontolerant male rats and on the in vitro release of pituitary prolactin. Japanese Journal of Pharmacology 28(6): 803-810, 1978

Effect of posterior pituitary lobectomy on in vivo and in vitro secretion of prolactin in lactating rats. Endocrine 5(3): 285-290, 1996

Melatonin effects on prolactin secretion in pituitary-grafted male rats. Journal of Pineal Research 6(1): 33-41, 1989

Effect of neonatal administration of prolactin on pituitary secretion of prolactin and gonadotrophins in adult female rats. Journal of Endocrinology 59(2): 377-378, 1973

Serum and pituitary luteinizing hormone, follicle-stimulating hormone and prolactin levels in gonadectomized male, female and androgenized female rats treated with oestradiol benzoate. Journal of Endocrinology 59(2): 209-216, 1973

Possible role of prolactin on adrenal corticosterone secretion in pituitary grafted male rats. Journal of Steroid Biochemistry 25(supp-S1): 1, 1986