Histochemical, enzyme histochemical and ultrastructural investigation on the sperm-duct glands of Padogobius martensi (Pisces, Gobiidae)

The functions of the sperm-duct glands of Padogobius martensi were investigated by histochemical, enzyme histochemical and fine structural methods during the prereproductive and reproductive periods, i.e. during their maximum activity. The epithelium lining the spermduct gland tubules produces strongly acidic sulphomucins, probably conjugated with proteins and the variety of sulphomucins increases during the reproductive period when the exocrine epithelium is also involved in the phagocytosis of degenerating sperm cells. A contractile network of myoid cells surround the tubules. The gland interstitium contains cells similar in enzyme histochemical and ultrastructural features to the testicular interstitial cells (Leydig cell homologues). Unlike the latter, however, the interstitial cells of the sperm-duct gland are able to produce steroid glucuronides, which act possibly as pheromones.