Exposure of mouse blastocysts in vitro to acidified media effective in dissolving the zona pellucida (Gwatkin, 1964), was reported to be incompatible with the survival of the blastocyst (Bowman & McLaren, 1969). It has been concluded that decreased pH is unlikely to be responsible for the lysis of the zona pellucida in utero (Bowman & McLaren, 1970). This conclusion was drawn from data concerning the effect of a prolonged exposure (up to several hours) of eggs to acidity in vitro. Evidence is reported here to show that the dissolution of the zona pellucida by a brief exposure of the blastocyst to acidity is compatible with its viability and subsequent development.
J. L. BRUN and A. PSYCHOYOS
V. BITTON-CASIMIRI, J. L. BRUN and A. PSYCHOYOS
Rat blastocysts, flushed from the uterus at the moment of the initiation of the implantation process and observed in vitro by time-lapse cinematography, were seen to undergo a series of contractions and dilatations. By these movements, vesicles, containing granular material, emerged through the zona pellucida into the culture medium.
V. Bitton-Casimiri, J. L. Brun and A. Psychoyos
Laboratoire de Physiologie de la Reproduction, CNRS, E.R. 122, Hôpital de Bicêtre (INSERM), 94270 Bicêtre, France