Histological Characteristics of Spermatogenesis in Testes of the Orangutan (Pongo pygmaeus)

Abstract

To make clear characteristics of spermatogenesis in testes of the orangutan (Pongo pygmaeus), we carried out a histological study using testicular samples from two individuals. Seminiferous epithelia were thick and those with the typical spermatogenetic cell arrangement were predominant. The interstitial tissue was abundant with many collagen fibers. The acrosomic system was clearly observed. We noticed twelve steps in the spermiogenesis. We could identify ten stages in a seminiferous cycle. We discussed characteristics of spermatogenetic patterns in the orangutan, comparing with the human, chimpanzee and gorilla.