Dietary effects on certain adrenal cortical functions in the rat.
The rate-limiting step in adrenal steroidogenesis is associated with the mitochondrial-cytochrome-P450scc-dependent production of pregnenolone from cholesterol. This sterol side-chain cleavage reaction is influenced by the supply of cholesterol to the mitochondria. Cholesterol is stored as cholesterol esters while the cytosol contains a hormone-sensitive cholesterol ester hydrolase. This enzyme is activated by phosphorylation involving a cyclic AMP-dependent protein kinase and ATP; this enzyme preferentially attacks cholesterol oleate or cholesterol linoleate. The lipid composition of the adrenal cortex is influenced by diet so that animals on a low-fat diet tend to store cholesterol oleate and as the linoleate content of the diet is increased, the cholesterol linoleate content of the adrenal cortex increases. Animals maintained on a high erucate diet tend to store large amounts of cholesterol erucate in the adrenal cortex; such animals have an impaired adrenal cortical function. Animals maintained on a low-fat diet (marginally deficient in essential fatty acids), a linoleate-replete diet or a moderate erucate diet, all exhibited normal responses to ACTH and normal corticosterone production rates.
D000302:Adrenal Cortex / Q000502:physiology*; D000305:Adrenal Cortex Hormones / Q000096:biosynthesis; D000324:Adrenocorticotropic Hormone / Q000502:physiology; D000818:Animals; D002788:Cholesterol Esters / Q000378:metabolism; D003345:Corticosterone / Q000096:biosynthesis; D000242:Cyclic AMP / Q000502:physiology; D003577:Cytochrome P-450 Enzyme System / Q000502:physiology; D004041:Dietary Fats / Q000494:pharmacology*; D008928:Mitochondria / Q000502:physiology; D051381:Rats; D002787:Sterol Esterase / Q000378:metabolism
D000305:Adrenal Cortex Hormones; D002788:Cholesterol Esters; D004041:Dietary Fats; D000324:Adrenocorticotropic Hormone; D003577:Cytochrome P-450 Enzyme System; D000242:Cyclic AMP; D002787:Sterol Esterase; D003345:Corticosterone