CYCLICAL CHANGES IN AND SIGNIFICANCE OF LIPIDS AND ACID PHOSPHATASE ACTIVITY IN THE SEMINIFEROUS TUBULES OF THE RAT TESTIS.

Abstract

AbstractThe distribution of tubular lipids and acid phosphatase activity was studied in the rat testis and in the ductuli efferentes. The results were referred to the stage of the cycle of the seminiferous epithelium. The significance of the lipids and phosphatase of the ducts was tested in animals, where excretory ducts were separated from testis for 30 to 40 days.During the acrosome phase of the old generation of spermatids the lipids first made their appearance in the cytoplasm. During the subsequent stages of the cycle (II to VIII) both the amount of lipids and the intensity of the acid phosphatase activity gradually increased, reaching a maximum in the cytoplasmic “split‐offs” of the mature sperm at stage VIII. Most of the lipids, together with phosphatase‐positive cytoplasmic granules were discarded with the spermatozoa, but a small proportion underwent phagocytosis by the Sertoli cells. During stage IX both lipid‐ and phosphatase‐positive particles moved to the periphery of the tubules as their number in the basal cytoplasm of the Sertoli cells rapidly increased. Through the stages IX to II a gradually diminishing amount of lipids and acid phosphatase activity was seen forming a peripheral ring in the tubules. A temporary rise in the Sertoli cell phosphatase activity took place at the time when the nuclei of the maturing spermatids were deep in the seminiferous epithelium (stages IV and V).Lipid droplets associated with acid phosphatase activity were present in the epithelium of ductuli efferentes of intact rats. Ductectomy caused a complete disappearance of the epithelial lipids. Simultaneously, cysts filled with degenerating spermatozoa and abundant lipids formed on the cut surface of the testis. It is concluded that the main part of the residual cytoplasm of the spermatids forms an apocrine secretion which is presumably absorbed in the ductuli efferentes and in other parts of the excretory duct system.