Search

In many species a series of Ca2+ oscillations is the first event triggered by egg-sperm fusion (Whitaker and Swann 1993). It is widely accepted that this series of increases in intracellular free Ca2+ is responsible for the following egg activation; however, the molecular mechanisms underlying such Ca2+ mobilization within the egg are not fully understood (Kline and Kline 1992; Whitaker and Swann 1993; Homa et al. 1993; Berridge 1996).

Spermatogenesis is a complex differentiative process, highly conserved in the course of evolution, represented by the ordered sequence of mitotic, meiotic and differentiative stages. The pioneering work of Oakberg (1956), Monesi (1965) and Clermont (1972) have clearly shown that these stages are characterized by a complex series of biosynthetic processes which make spermatogenesis an excellent model system for the study of molecular events related to cell differentiation. DNA, RNA and protein synthesis were initially studied by autoradiographic and histochemical techniques, and only later with biochemical analysis after the introduction of cell fractionation techniques (Lam et al., 1970; Meistrich, 1973) which made available germ cells at defined stage of differentiation. Further insight into the genetic events and the mechanisms which control germ cell differentiation seems now possible with the use of powerful tools like molecular biology and transgenic techniques.