Rabbit Sperm Reversible Decapacitation by Membrane Stabilization with a Highly Purified Glycoprotein from Seminal Plasma

Mouse sperm capacitation in vitro involves loss of a surface-associated inhibitory component

“…There was no inhibition of the guinea-pig acrosome reaction by the inhibitory factor purified from human seminal plasma (Reddy, Audhya, Goodpasture & Zaneveld, 1982). Despite this, the majority of investigations looking at possible interaction between male reproductive tract fluids and the acrosome (Davis & Niwa, 1974;Bavister, Rogers & Yanagimachi, 1978;Eng & Oliphant, 1978;Fleming & Wai, 1978;Hyne & Garbers, 1982) have indicated an inhibition of the acrosome reaction, findings consistent with those in the present study.…”

“…The active component from porcine epididymal fluid is reported to be of low molecular weight (Hyne & Garbers, 1982), while those from human (Kanwar et al, 1979;Reddy et al, 1979) and rabbit (Davis & Niwa, 1974;Eng & Oliphant, 1978) …”

Metabolic and surface events in fertilization

“…As discussed briefly in the Introduction, the concept that capacitation involves, at least in part, the loss or removal of inhibitory molecules from the sperm surface is well established; in some species, the block to fertilization observed when inhibitor (decapacitation factor, DF) is added back to capacitated sperm is reversible with time [discussed fully by Oliphant et al, 19851. The mechanism of action associated with such DFs that is most consistent with experimental observation is one of stabilizing sperm membranes and thereby inhibiting the acrosome reaction [e.g., Davis and Niwa, 1974;Bavister et al, 1978;Eng and Oliphant, 1978;Fleming and Wai, 1978;Hyne and Garbers, 1982;Fraser, 1984bl. As mentioned earlier, the primary signal for the acrosome reaction appears to be an increase in intracellular calcium levels. Among specific candidates for DFs are proteins that have been shown to affect calcium transport mechanisms by promoting calcium efflux and that could thereby prevent the acrosome reaction [Rufo et al, 1982;Bradley and Forrester, 19821.…”

Characterization and androgenic regulation of major mRNAs coding for epididymal proteins in a lizard (Lacerta vivipara)

“…Although the physiological impacts of these interactions are not fully understood, they are related to sperm maturation. The role of epididymal glycoproteins in membrane stabilization (Eng & Oliphant, 1978;Thomas et al, 1984) or in the acquisition of the progressive motility of immature spermatozoa (Acott & Hoskins, 1981) has been demonstrated in some cases. Sperm maturation is androgen-dependent and requires RNA synthesis and epididymal protein synthesis (Orgebin-Crist & Jahad, 1978).…”