These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Mechanism of action of prolactin on adrenocortical steroid secretion in hypophysectomized female rats.
    Author: Colby HD.
    Journal: Endocrinology; 1979 May; 104(5):1299-303. PubMed ID: 220030.
    Abstract:
    Studies were carried out to determine the actions of PRL on adrenocortical function in hypophysectomized female rats in the presence and absence of ACTH. PRL administration alone decreased 5 alpha-reductase activity but did not significantly affect the rates of corticosterone secretion or peripheral plasma corticosterone concentrations. The activities of several steroidogenic enzymes (cholesterol desmolase, 11 beta-hydroxylase, and 21-hydroxylase) were also unaffected by PRL. Adrenal steroidogenesis was increased by ACTH treatment, as expected, resulting in an increase in corticosterone secretion. However, since adrenal 5 alpha-reductase activity was higher in ACTH-treated hypophysectomized rats than in normal animals with intact pituitary glands, large amounts of 5 alpha-dihydrocorticosterone (DHB) and 3 beta, 5 alpha-tetrahydrocorticosterone (THB) were also secreted. PRL, when administered in combination with ACTH, potentiated the effecte levels. PRL did not affect cholesterol side chain cleavage, 11 beta-hydroxylation, or 21-hydroxylation in ACTH-treated rats. However, administration of PRL to ACTH-treated rats lowered adrenal 5 alpha-reductase activity, decreasing DHB and THB secretion. The decrease in DHB and THB secretion approximated the increase in corticosterone output. The results indicate that, in the presence of ACTH, PRL increases corticosterone secretion by decreasing intraadrenal degradation of corticosterone and not by enhancing steroidogenesis.
    [Abstract] [Full Text] [Related] [New Search]