Obligatory Role of the δ 5 -Bond of Cholesterol for Steroid Formation by Adrenal Preparations

Abstract

Summary

The δ⁵-bond appears to be a very specific requirement for the formation of steroids from cholesterol. Rat and hog adrenal homogenates were incapable of converting tracer amounts of radioactive dihydrocholesterol to labeled steroids to any significant extent. This inability was not due to competitive inhibition by cholesterol since cholesterol-extracted acetone powder preparations of beef adrenal mitochondria or homogenates of adrenals with high levels of dihydrocholesterol were similarly unable to effect a significant conversion. Steroid synthesis from radioactive cholesterol was substantially inhibited in homogenates of adrenals from rats fed dihydrocholesterol while the total amount of cholesterol in these adrenals was increased as compared to that of normal rats.