Shears S B, Boyd G S
Eur J Biochem. 1982 Mar;123(1):153-7. doi: 10.1111/j.1432-1033.1982.tb06511.x.
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 synthesised pregnenolone was attained after 2 min at 30 degrees 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.
借助通过硅油离心快速从孵育物中分离细胞器的方法，测定了孕烯醇酮从牛肾上腺皮质线粒体中的流出情况。在不存在牛血清白蛋白或胞质上清液（100000×g）的情况下，在30℃孵育2分钟后，新合成的孕烯醇酮达到平衡分布；总孕烯醇酮的20%位于线粒体外。每毫升含有13毫克白蛋白或13毫克上清液蛋白可分别将孕烯醇酮的外源比例提高到90%以上和75%以上，而不影响胆固醇侧链裂解的速率。白蛋白和上清液对孕烯醇酮的结合均为非特异性且不饱和的。提示在体内线粒体膜对孕烯醇酮从细胞器中流出并不构成显著障碍。
