Cholesterol side-chain cleavage enzyme activity and cytochrome P-450 content in adrenal mitochondria of a patient with congenital lipoid adrenal hyperplasia (Prader disease)

Abstract An autopsied case with congenital lipoid adrenal hyperplasia (Prader disease) was presented. The cholesterol side-chain cleavage (SCC) enzyme activity in adrenal mitochondria of this case was assayed with [ 3 H]cholesterol as substrate, combined with purified bovine adrenodoxin and adrenodoxin reductase, by measuring the amount of [ 3 H]pregnenolone formed. The cytochrome P-450 content was also measured by recording the difference absorption spectra of carbon monoxide-complexed P-450. The cholesterol SCC enzyme activity in adrenal mitochondria of Prader disease was 0.81 nmol pregnenolone/nmol P-450 per min, which was approximately 10% of that in normal tissue. The content of cytochrome P-450 was 0.074 nmol/mg protein, which was about half of that in controls. These results indicate that there is a cholesterol SCC enzyme deficiency in adrenal mitochondria in this disease.