Changing Relationships between Testis Size, Sertoli Cell Number and Spermatogenesis in Sprague‐Dawley Rats

Abstract

Relationships between several reproductive characteristics were investigated in 25 Sprague‐Dawley rats aged 60, 150, and 240 days (n = 75). Daily sperm production correlated with body weight (r = 0.63), paired testes weight (r = 0.68), testes weight as a percentage of body weight (r = −0.50), the number of spermatids supported per Sertoli cell (r = 0.51) and the number of Sertoli cells per gram (r = 0.89) or per testis (r = 0.95) among rats pooled across age groups. In general, the number and magnitude of significant coefficients of correlation were decreased when calculated within age groups. The latter often appeared to reflect a statistical consequence of relative homogeneity among rats rather than the absence of a biological relationship. However, the total number of Sertoli cells per testis correlated with daily sperm production within age groups, and could account for 85 to 94% of the variability in sperm production at 150 and 240 days, respectively. 1990 American Society of Andrology