title: The relationship between energy generation and cholesterol side-chain cleavage reaction in the mitochondria from human term placenta.
abstract: 1. The interrelationship between progesterone (from cholesterol) biosynthesis and oxidative phosphorylation in human placental mitochondria was examined. 2. ADP and ATP stimulated the malate, succinate and alpha-ketoglutarate-supported progesterone biosynthesis probably via the energy-dependent pyridine nucleotide transhydrogenase activation. The effect of ADP was abolished by rotenone and antimycin in the presence of malate or alpha-ketoglutarate. 3. In the non-energized state of mitochondria malate may supported progesterone biosynthesis by the malic enzyme-dependent pathway. 4. The inhibitory effects of antimycin or cyanide, and the stimulatory effect of rotenone on the succinate-supported progesterone biosynthesis indicate that the succinate to malate conversion is a necessary condition for the stimulation of progesterone biosynthesis from cholesterol. 5. alpha-Ketoglutarate plus malonate did support progesterone biosynthesis also in the presence of ADP or ATP and to a lesser degree in the presence of DNP and rotenone. Arsenate in the presence of alpha-ketoglutarate, malonate, dinitrophenol and rotenone did not affect significantly progesterone biosynthesis. These results indicate that NADPH may be generated also by a non-energy-dependent transhydrogenation in placental mitochondria.
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D002784:Cholesterol / Q000378:metabolism*; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008928:Mitochondria / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011374:Progesterone / Q000096:biosynthesis*; D013386:Succinates / Q000494:pharmacology
chemical_list: D013386:Succinates; D011374:Progesterone; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D002784:Cholesterol