The role of the phosphatidate-inositide cycle in the action of steroidogenic agents.
Most steroidogenic agents have been found to provoke rapid changes in the metabolism of phospholipids in the phosphatidate-inositide cycle. These changes include: (a) de novo synthesis of phosphatidic acid and its derivatives, phosphatidylglycerol, mono- and polyphosphoinositides and diglyceride; and (b) phosphatidylinositol hydrolysis and consequent generation of diglyceride and phosphatidic acid. The de novo phosphatidate synthesis effect occurs in the action of all tested steroidogenic agents (ACTH, LH, angiotensin, K+, serotonin) and may be induced by either of the "second messengers", cAMP and Ca2+. The phosphatidylinositol hydrolysis effect(s) occurs only in the action of steroidogenic agents that operate via Ca2+ (angiotensin and K+) and may be important in Ca2+ mobilization. The de novo phospholipid effect correlates well with changes in steroidogenesis and, like the latter, requires Ca2+ and protein synthesis; from these and other results, it seems likely that this phospholipid effect plays an important role in the stimulation of steroidogenesis.
D000311:Adrenal Glands / Q000187:drug effects / Q000378:metabolism*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000809:Angiotensins / Q000494:pharmacology; D000818:Animals; D002784:Cholesterol / Q000378:metabolism; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D010712:Phosphatidic Acids / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D013256:Steroids / Q000096:biosynthesis*
D000809:Angiotensins; D010712:Phosphatidic Acids; D010716:Phosphatidylinositols; D010743:Phospholipids; D013256:Steroids; D000324:Adrenocorticotropic Hormone; D003577:Cytochrome P-450 Enzyme System; D002784:Cholesterol; D000242:Cyclic AMP; D002786:Cholesterol Side-Chain Cleavage Enzyme; D011188:Potassium