Stage Dependent Variation in Mn²⁺⁻-Sensitive Adenylyl Cyclase (AC) Activity in Spermatids and FSH-Sensitive AC in Sertoli Cells

Abstract

The variation of the specific Mn²⁺-dependent adenylyl cyclase (AC) activity in spermatids and follicle stimulating hormone (FSH)-responsive AC activities in Sertoli cells in different stages (I-XIV) of the seminiferous epithelial cycle has been investigated. Maximal Mn²⁺-dependent AC activity was observed in stages II-III while minimal activity was encountered in stages VII-VIII (spermiation). FSH-responsive AC activity exhibited a pattern that coincided with that of the Mn²⁺-dependent AC. The stage-dependent variation in spermatid AC activity cannot be explained by altered numbers of haploid cells. This raises the question whether the Sertoli cells may regulate the spermatid AC activity. Sertoli cells in various stages are all exposed to the same concentration of circulatory hormones. Hence the stage-dependent difference in FSH-responsiveness indicates that local influences (from germ cells?) may regulate the response of the AC in Sertoli cells to FSH.

Key Words:

• Testis
• Stages
• Spermatids
• Sertoli cells
• Adenylyl cyclase.