Search

Pregnenolone efflux from bovine adrenal cortex mitochondria was measured with the aid of rapid separation of the organelles from the incubation by centrifugation through silicon oil. In the absence of bovine serum albumin or cytosolic supernatant (100 000 x g), an equilibrium distribution of newly synthesized pregnenolone was attained after 2 min at 30 C; 20% of total pregnenolone was located outside the mitochondria. The presence of 13 mg albumin/ml or 13 mg supernatant protein ml increased the exogenous proportion of pregnenolone to over 90% and 75% respectively without affecting the rate of cholesterol side-chain cleavage. The binding of pregnenolone by both albumin and supernatant was non-specific and non-saturable. It is suggested that in vivo the mitochondrial membranes do not present a significant barrier to pregnenolone efflux from the organelle. [ABSTRACT FROM AUTHOR]

Examines the effect of azastene, cyanoketone and trilostane upon respiration and cleavage of the cholesterol side chain in mitochondria from bovine adrenal cortex. Prevention of pregnenolone metabolism; Assay of cholesterol side-chain cleavage; Function of cyanoketone and trilostane as inhibitors of pregnenolone metabolism; Incubation with adenosine diphosphate.