Testicular feminization of the mouse. Paucity of peroxisomes in Leydig cells of the testis

The testes of mice with the X-linked testicular feminization (Tfm/y♀/♂) mutation are very small and cryptorchid. The spermatogenesis in the adult Tfm/y♀/♂ mouse testes is arrested, and the testosterone biosynthesis is significantly reduced due to deficiency of 17-ketosteroid reductase the enzyme essential for the conversion of androstanedione to testosterone. In this study the distribution of peroxisomes in the Leydig cells of adult Tfm/y♀/♂ mice was investigated because of the suggestion that peroxisomes may participate in lipid metabolism and/or androgen biosynthesis in steroidogenic cells. Aldehyde-fixed testicular tissue of Tfm/y♀/♂ mice was processed for the cytochemical localization of peroxisome catalase to facilitate identification of these organelles in the Leydig cells. Testes from Blo/y and CS(a) strain normal adult mice served as controls. Testicular Leydig cells of normal adult Blo/y and CS(a) mice contained abundant smooth endoplasmic reticulum (SER) in the form of complex interconnected tubules and double-walled membranous vesicles. Numerous peroxisomes, often in continuity with SER channels or in close association with lipid droplets, were observed in Leydig cells of normal males. In contrast, the peroxisomes in the Leydig cells of adult Tfm/y♀/♂ mouse testes were either undiscernible or greatly reduced in number and size. SER in these cells was sparse, whereas mitochondria were numerous. In addition, abundant clusters of lipid droplets were encountered in a majority of Leydig cells of Tfm/y♀/♂ mouse testes. Peroxisome and SER paucity in Leydig cells of Tfm/y♀/♂ mice may be a reflection of reduced testosterone production. Whether excessive accumulation of lipid in the Leydig cells of Tfm/y♀/♂ mouse testes is due to reduced utilization of cholesterol for the biosynthesis of testosterone or to impaired lipid metabolism due to reduction in peroxisome population in these cells remains to be ascertained.