Testosterone Secretion by Rat, Rabbit, Guinea Pig, Dog, and Hamster Testes Perfused in Vitro: Correlation with Ley dig Cell Ultrastructure*

Abstract

Stereological methods were employed to determine volume and surface densities of cytoplasmic organelles in Leydig cells of hamster, rat, rabbit, dog, and guinea pig testes. Contralateral testes were perfused in vitro with maximally stimulating gonadotropin concentrations to determine the capacity of these testes to secrete testosterone. Significantly different amounts of testosterone were secreted by in vitro perfused testes of the five species when maximally stimulated with ovine LH. Significant differences also were seen in the volume and surface densities of smooth endoplasmic reticulum, mitochondria, rough endoplasmic reticulum, and lipids in Leydig cell cytoplasm of the five species. Most interestingly, linear positive correlations were seen between testosterone secretion and smooth endoplasmic reticulum volume (r = 0.99) and surface (r = 0.99) densities. Thus, virtually all of the differences in testosterone secretion by maximally stimulated testes of five species could be accounted for by between-species differences in the amount of Leydig cell smooth endoplasmic reticulum.

Interbular space characterization in adult capybara (Hydrochoerus hydrochaeris) testis

“…In vitro studies correlating the structure and function of the Leydig cells in several mammal species showed that the variations in testosterone secretion resulted more from the individual ability of this cell in secreting testosterone than from differences in the total volume of these cells (Ewing et al, 1979). This ability is highly associated to the amount of the smooth endoplasmic reticulum present in the Leydig cell (Zirkin et al, 1980). The well-known high production of testosterone does not justify the wide variation observed for the percentile occupied by Leydig cells in testicle.…”

Effects of Ethanol Treatment on Leydig Cellular NADPH-Generating Enzymes and Lipid Profiles.

“…Moreover, the number of elongated and cup-shaped mitochondria and cytoplasmic pseudopods were increased. Reduction in endoplasmic reticulum was predicted to decrease in steroidogenic activity [9]. Orpana et al [10,11] have shown that the metabolites involved in substrate shuttles maintaining the NAD(P)H redox state regulate steroidogenesis.…”

Histomorphometric evaluation of the testicular parenchyma of rats submittedto protein restriction during intrauterine and postnatal life

“…This fact may be explained by an increase in cytoplasmic and Leydig cell volumes. According to Ewing et al (1979), Zirkin et al (1980), Mendis-Handagama et al (1988), and Navarro et al (2004), the steroidogenic capacity of Leydig cells is directly related to the amount of smooth endoplasmic reticulum, and cytoplasmatic and cellular volume are more important than the number of cells.…”