Effects of a cholesterol-rich-diet and a hypolipidemic drug (clofibrate, CPIB) on Leydig cells in rats stereological and biochemical analysis.

Although the plasma testosterone level of the cholesterol-fed animals was almost the same as that of the control animals, the concentration in the tissue of the testis of the cholesterol group was 50% higher than that of the control group. Stereological data showed that the smooth endoplasmic reticulum of Leydig cells of the cholesterol group decreased by respectively 38 and 32% in volume as well as in surface area, and also mitochondria decreased by respectively 27 and 22% in volume as well as in surface area of inner membrane, as compared with the control group. Lipid droplets decreased remarkably in number and volume. Consequently Leydig cells of the cholesterol group diminished their cell volume to 83% of that of the control. When clofibrate was administered, the testosterone concentration in the testis tissue increased to 2.3 times that of the control group, although the plasma testosterone level was almost the same. In the Leydig cells of animals treated with cholesterol plus clofibrate peroxisomes decreased significantly and lipid droplets increased noticeably, as compared with the cholesterol-fed animals. These results might suggest that the testosterone production rate will decrease if the animals are fed for a longer period on a cholesterol-rich diet or immediately after the chow turns to a low-cholesterol-diet, and that the peroxisomes in the Leydig cells differ in their functional roles from those in the liver.