Effects of Steroids and ACTH on Pyruvate and Acetate Metabolism by the Sheep Adrenal Cortex in Vitro1

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Abstract
Fasciculate-reticular slices of sheep adrenal cortex were incubated for 1 hr. in Krebs-Henseleit solution containing glucose 5 mM and then for 3 hr. in solution contain-ing pyruvate-3-14C. Adrenal tissue from sheep treated for 1 week with triamcinolone acetonide, 0.1 mg/kg/day, showed a significant decrease in 14c incorporation into tissue cholesterol. A direct effect of steroids on adrenal lipid metabolism was studied by incubating adrenal cortical slices with cortisol sodium succinate 6.7 x 10-4M. The addition of cortisol was accompanied by a significant increase in 14C incorporation into medium bicarbonate and by significant decreases in 14C incorporation into fatty acids and cholesterol. ACTH in concentrations of 1.0 and 0.1 U/ml resulted in similar effects [long dash]increased 14C incorporation into medium bicarbonate, decreased 14C incorpora-tion into adrenal cortical fatty acids and cholesterol. Modified pulse-labeling studies with acetate-2-14C revealed an early phase of dispro-portionate labeling of adrenal cortical cholesterol. This early phase of 14C-cholesterol formation was significantly decreased by adding ACTH 0.1 U/ml to the incubation medium. ACTH consistently reduced tissue cholesterol concentrations.