A Comparative Study of Daily Sperm Production and Testicular Composition in Humans and Rats

Determination of the elongate spermatid--Sertoli cell ratio in various mammals

“…The results of the present study, specifically referring to the rat, indicate a slightly higher sperm production rate than that calculated by Wing & Christensen (13-42 106/testis; 9-61/g testis), yet a lower production rate than that cited by Johnson et al (1980) for homogenization techniques (35-4 106 and 20-0 106, respectively), or for histometric techniques 106 and 15-03 respectively). These data parallel our elongate spermatid-Sertoli cell ratio (although a time divisor was not utilized) data in a comparative sense, and fit our hypothesis that the elongate spermatid-Sertoli cell ratio is a basic determinant of spermatogenic efficiency.…”

“…For example, the sperm production in man is similar to that of the rat, although there is a 10-fold difference in testicular mass (Johnson, Petty & Neaves, 1980). This difference was partly due to the higher proportion of area occupied by the intertubular and boundary tissue in men, but when comparisons of testicular (tubular) parenchyma in rats and men were made, the rat was about 7 times more efficient (Johnson et al, 1980). Micrographs in Figure 4 of Johnson et al (1980) elegantly depict the relative abundance of spermatids and relative sparcity of Sertoli cells in the rat as compared with man.…”

“…Certainly, other factors such.as the percentage area which is occupied by seminiferous tubules versus intertubular space or the duration of the cycle of the seminiferous epithelium would be a factor in these determinations. For example, the sperm production in man is similar to that of the rat, although there is a 10-fold difference in testicular mass (Johnson, Petty & Neaves, 1980). This difference was partly due to the higher proportion of area occupied by the intertubular and boundary tissue in men, but when comparisons of testicular (tubular) parenchyma in rats and men were made, the rat was about 7 times more efficient (Johnson et al, 1980).…”

“…This difference was partly due to the higher proportion of area occupied by the intertubular and boundary tissue in men, but when comparisons of testicular (tubular) parenchyma in rats and men were made, the rat was about 7 times more efficient (Johnson et al, 1980). Micrographs in Figure 4 of Johnson et al (1980) elegantly depict the relative abundance of spermatids and relative sparcity of Sertoli cells in the rat as compared with man. The elongate spermatid-Sertoli cell ratio is probably therefore the reason for the dramatic difference in sperm production in rat and man.…”

Fascin 1 is an actin filament-bundling protein that regulates ectoplasmic specialization dynamics in the rat testis

“…This is necessary so that upwards of 300 million or 30 million to 50 million sperms can be produced each day from the testes of an adult male in humans or rodents, respectively (2,5,25). Furthermore, Sertoli cells in the testis are also polarized cells that are manifested by the unique localization of 1) the nucleus near the basement membrane, 2) lysosomes in the basal compartment that are used to process phagosomes derived from the residual bodies that are transported from the adluminal compartment at stage VIII of the epithelial cycle (15), and 3) the presence of tight junction (TJ), basal ectoplasmic specialization [ES; a testisspecific adherens junction (AJ)], and desmosome at the bloodtestis barrier (BTB) near the basement membrane.…”