Human anencephalic adrenal tissue: low density lipoprotein metabolism and cholesterol synthesis.

Abstract

It has been shown that lipoproteins and, specifically, low density lipoprotein (LDL) are the principal source of cholesterol utilized for steroidogenesis in normal human fetal adrenal (HFA) tissue. ACTH causes an increase in the number of LDL receptors and in the rate of degradation of LDL as well as an increase in de novo synthesis of cholesterol in normal HFA tissue. In a previous investigation, we found that cortisol synthesis in ACTH-treated adrenal tissue obtained from an anencephalic newborn was not stimulated further by the addition of lipoprotein-cholesterol. In the present investigation, we sought to ascertain whether adrenal tissue from anencephalic newborns could bind LDL and if ACTH could increase the rate of metabolism of LDL by this tissue. The rate of cholesterol synthesis in adrenal tissue from anencephalic newborns was determined by measuring 1) the rate of incorporation of [14C]acetate into cholesterol, 2) the specific activity of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase...