Spermatogenesis in leeches II: The effect of the supraesophageal ganglion and ventral nerve cord ganglia on spermatogenesis in the North American medicinal leech Macrobdella decora

Abstract

Spermatogenesis in the leech Macrobdella decora was analyzed according to five sequential developmental stages. Sexually mature leech testes contained all five stages. Sexually immature leeches, however, contained only the first three stages. Injections of homogenates of supraesophageal ganglia from sexually mature leeches into decerebrate mature leeches promoted the later, presumably meiotic, stages of spermatogenesis. Subesophageal ganglionic homogenates failed to promote production of spermatids. On the other hand injections of the same supraesophageal homogenates into decerebrate immature leeches conspicuously failed to promote the later stage of spermatogenesis. However, the total number of spermatic follicles in the testes were significantly elevated over other nervous tissue homogenate and saline-treated and intact leeches. Following injection of ventral nerve cord homogenates into immature animals the total number of follicles in the testes, while not significantly different from nondecerebrated control leeches, was significantly greater than those in saline, subesophageal and posterior ganglion-treated leeches. The data support the concept of a factor or factors from the supraesophageal ganglion influencing not only the later, presumably meiotic stages of spermatogenesis, but also the early stages. Furthermore the experimental evidence invokes the concept of a factor from the ventral nerve cord having an influence on the early stages of spermatogenesis.