Prevention of fertilization in vitro by an acrosin inhibitor from rete testis fluid of the ram.

Abstract

One of the enzymes probably involved in sperm penetration through the outer layers of the ovum is a trypsin-like enzyme, called acrosin because of its location in the acrosome. This enzyme is inhibited by substances found in semen and in the secretion of seminal vesicles of several mammalian species (see Werle & Zickgraf-Rüdel, 1972). It is generally thought that the spermatozoa mix with these inhibitors during ejaculation, and a complex between the inhibitors and the acrosin is formed at that time (Zaneveld, Polakoski, Robertson & Williams, 1971; Werle & Zickgraf-Rüdel, 1972). Removal of these inhibitors from the acrosome is supposed to be an essential part of the process of capacitation and the acrosome reaction (see Bedford, 1970). Several attempts have been made to prevent fertilization with synthetic or natural trypsin inhibitors, and