Stimulation of progesterone production by phorbol-12-myristate 13-acetate (PMA) in cultured Leydig tumor cells
It has been shown that addition of hCG or c-AMP to cultured Leydig tumor cells (MA-10) increases synthesis of progesterone as the major steroid. To investigate the possible involvement of protein kinase C (PK-C) in the regulation of steroid synthesis, the authors have studied the effect of PMA, an activator of PK-C, on progesterone production in MA-10 cells. The addition of PMA (100 ng/ml) stimulated steroid production whereas 4 -phorbol-12,13-didecanoate, an inactive phorbol ester, did not have any effects. Like hCG and c-AMP, PMA-stimulated progesterone production was inhibited by cycloheximide. hCG-stimulated steroid synthesis was inhibited by PMA. The addition of PMA to MA-10 Leydig cells further increased the c-AMP-stimulated progesterone production. To determine whether c-AMP has a obligatory role in the regulation of steroid production, the effect of adenylate cyclase inhibitor, 9-(tetrahydro-2-furyl)adenine (TFA), was studied on progesterone production in the presence of hCG. At lower dose (17 ng/ml) hCG-stimulated intracellular c-AMP levels and steroid production were inhibited by TFA (300 M). At higher dose of hCG (34 ng/ml) TFA did not inhibit the hCG-stimulated intracellular c-AMP levels, however, progesterone production was inhibited. Results suggest that the action of hCG, c-AMP and PMA in controlling steroidogenesis might be regulated by similar but different mechanisms.
- Research Organization:
- Texas Technical Univ. Health Sciences Center, Lubbock
- OSTI ID:
- 6150220
- Report Number(s):
- CONF-870644-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 46:6; Conference: 78. annual meeting of the American Society of Biological Chemists conference, Philadelphia, PA, USA, 7 Jun 1987
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PHORBOL ESTERS
BIOLOGICAL EFFECTS
PHOSPHOTRANSFERASES
BIOCHEMICAL REACTION KINETICS
PROGESTERONE
BIOSYNTHESIS
AMP
CELL CULTURES
ENZYME INHIBITORS
TUMOR CELLS
ANIMAL CELLS
CARCINOGENS
ENZYMES
ESTERS
HORMONES
KETONES
KINETICS
NUCLEOTIDES
ORGANIC COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
PREGNANES
REACTION KINETICS
STEROID HORMONES
STEROIDS
SYNTHESIS
TRANSFERASES
560300* - Chemicals Metabolism & Toxicology