DURATION OF SPERMATOGENESIS AND RELATIVE FREQUENCY OF EACH STAGE IN THE SEMINIFEROUS EPITHELIAL CYCLE OF THE CHIMPANZEE

To determine the duration of 1 spermatogenic cycle, a single pulse of tritiated thymidine was infused into a branch of the spermatic artery in each of 3 chimpanzees (Pan troglodytes). Samples were recovered sur gically prior to infusion, at 1 h, and at 3, 8, 14, 16, 17, 28, 30, 33 , 40, 44, and 48 days post-infusion. Tissues were fixed in Bouin's sol ution, dehydrated, paraffin-embedded, sectioned at 5 micrometers, and stained. Pre-infusion samples were used in morphometric studies to est imate the percentage frequency of area occupied by each of the 6 cellu lar associations (stages I-VI) characteristic of chimpanzee spermatoge nesis, and thus, to estimate the days duration of each stage. To estim ate the duration of 1 spermatogenic cycle, pre- and post-infusion, tis sue sections were coated with undiluted Kodak NTB2 liquid autoradiogra phic emulsion and incubated at 4+/-1 degrees C, At optimum exposure ti mes, slides were processed with Kodak D-19 and Fixer; light microscopi c analyses were conducted to determine the most mature labeled cell in Stage III for each of the sample times, The duration of the 6 stages (I-VI) are 4.2, 2.0, 4.3, 1,5, 1.3 and 0.6 days, respectively, and the duration of 1 spermatogenic cycle is approximately 14 days. Thus, the duration of spermatogenesis from the Ap spermatogonium to mature Sd2 spermatid is approximately 62.5+/-1.5 days or 4.46 spermatogenic cycle s.