Isolation and Biochemical Studies of Enriched Populations of Spermatogonia and Early Primary Spermatocytes from Rat Testes1

Abstract
A method to obtain several highly enriched populations of testis cell types from rats of a single age is described. Single cell suspensions from immature rat testes were prepared after enzymatic removal of interstitial cells. Cells were separated on the basis of size into four fractions (bulk preparations) or eight fractions (analytical preparations) by centrifugal elutriation. These elutriator fractions where further separated by equilibrium density centrifugation in Percoll gradients. In this manner, populations of 2 .times. 107 type A spermatogonia (51% purity) 3 .times. 107 type B spermatogonia (76% purity), 5 .times. 107 zygotene/early pachytene spermatocytes (56% purity), 3 .times. 107 midpachytene spermatocytes (70% purity), and 4 .times. 107 Sertoli cells (89% purity) could be obtained from 50 immature rats within 6 h after killing. Purities, determined by examination of cytologic smears, were verified by Coulter volume and flow cytometric DNA determinations. These separation methods were used to obtain cell populations for characterization of levels and synthesis of high mobility group proteins in the early stages of spermatogenesis.