The steroidogenic acute regulatory protein is induced by angiotensin II and K+ in H295R adrenocortical cells.
Adrenal steroid hormone biosynthesis can be activated by the protein kinase A pathway by ACTH, the protein kinase C pathway by angiotensin II (AII), or by increasing intracellular Ca2+ levels by AII or K+. Although their mechanisms of action are not known, each of these pathways is dependent upon the de novo synthesis of a protein that is required for the acute production of steroids. We have recently proposed the steroidogenic acute regulatory (StAR) protein as this required protein, therefore, we examined the effect of different agonists on StAR's expression in H295R human adrenocortical carcinoma cells. (Bu)2cAMP, AII, K+, BAYK8644 (a calcium channel agonist) and TPA are all shown to induce StAR. Aldosterone synthesis was stimulated by all the agonists with the exception of TPA, indicating that AII-stimulated steroid production is mediated by increases in intracellular calcium. Thus, these data suggest that regulation of StAR expression may represent a common mechanism for divergent pathways to acutely control adrenal steroidogenesis.
Clark
B J
BJ
Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock 79430, USA.
Pezzi
V
V
Stocco
D M
DM
Rainey
W E
WE
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000450:Aldosterone / Q000378:metabolism*; D000804:Angiotensin II / Q000494:pharmacology*; D003994:Bucladesine / Q000494:pharmacology; D002120:Calcium Channel Agonists / Q000494:pharmacology; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000819:agonists*; D006801:Humans; D010750:Phosphoproteins / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology*; D011493:Protein Kinase C / Q000819:agonists; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors; D000098682:Steroidogenic Acute Regulatory Protein
D002120:Calcium Channel Agonists; D010750:Phosphoproteins; D000098682:Steroidogenic Acute Regulatory Protein; D000804:Angiotensin II; D000450:Aldosterone; D003994:Bucladesine; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D011188:Potassium