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: Stimulation of progesterone production by phorbol-12-myristate-13-acetate in MA-10 Leydig tumor cells.
    Author: Chaudhary LR, Stocco DM.
    Journal: Biochimie; 1988 Oct; 70(10):1353-60. PubMed ID: 2852964.
    Abstract:
    The tumor-promoting phorbol ester, phorbol-12-myristate-13-acetate (PMA) markedly stimulated progesterone production in MA-10 Leydig tumor cells. A slight but significant increase (35%) in the activity of the cholesterol side-chain cleavage (CSCC) enzyme was observed in mitochondria isolated from the PMA-treated MA-10 Leydig cells when compared to mitochondria isolated from non-treated cells. However, this stimulation of CSCC activity appears to be of limited importance when compared to the 240-fold increase observed in progesterone production following PMA stimulation. In contrast, the inactive phorbol ester 4 alpha-phorbol-12,13-didecanoate (alpha-PD) had no effect on either progesterone production or CSCC activity. PMA had no effect on the conversion of 25-hydroxycholesterol and 22R-hydroxycholesterol into progesterone suggesting that one of the mechanism(s) of PMA action may involve the delivery of cholesterol to the mitochondria and/or the affinity of cholesterol with cytochrome P-450scc. Stimulation of steroidogenesis by PMA was also shown to be inhibited by cycloheximide. When PMA was added together with a submaximal dose of hCG, hCG-stimulated steroidogenesis was inhibited. However, at a maximal dose of human chorionic gonadotropin (hCG), PMA inhibited steroid synthesis at 1 and 2 h but had no significant effect at 3 h. Conversely, PMA had an additive effect on cAMP induced steroidogenesis. It was further demonstrated that PMA resulted in a decrease in the hCG-induced accumulation of cAMP.(ABSTRACT TRUNCATED AT 250 WORDS)
    [Abstract] [Full Text] [Related] [New Search]