Pharmacokinetics of zinc tannate after intratesticular injection

Forty-eight sexually mature male rats were injected intratesticularly with either 1, 3, or 6 mg zinc tannate (Kastrin) or with saline (as control). Zinc localized only in low concentration in primary spermatocytes and could not be detected in spermatogonia, Sertoli cells, spermatids, or spermatozoa. Forty-eight hours after injection of 1 mg Kastrin, zinc was accumulated in the spermatogonia and primary spermatocytes while, after injection of 3 mg, zinc was preferentially localized in Sertoli cells and spermatids; however, zinc was observed in the spermatids and spermatozoa 48 h after injection with 6 mg, and germ cells lost their identity and were fragmented after 1 week.