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

Criteria were devised for determining the elongate spermatid-Sertoli cell ratio in various mammalian species at the electron microscope level. When data from particular species were pooled, the values were: rabbit, 12.17:1, hamster, 10.75:1; gerbil, 10.64:1; rat, 10.32:1; guinea-pig, 10.10:1; vole, 9.75:1; and monkey, 5.94:1. The elongate spermatid-Sertoli cell ratio is a measure of the workload of the Sertoli cell and is a prime factor determining their efficiency. The higher the ratio, the higher the sperm output is likely to be per given weight of seminiferous tubule parenchyma for a particular species.