EFFECTS OF LOW CHRONIC ETHANOL EXPOSURE ON PROSTAGLANDIN-E SYNTHESIS BY PREIMPLANTATION MOUSE EMBRYOS

Embryo prostaglandin (PG) synthesis plays a role in the modulation of embryo metabolism and viability, and in the beginning of the implantat ion. The effects of ethanol consumption seem to be mediated at least i n part by PGs. Increased PG production of postimplantation embryos is associated with retardation and abnormalities in the gestational perio d. The aim of this study was to find out the effects of low chronic et hanol ingestion by mice, previous to pregnancy, on the PGE released by in vitro and in vivo derived embryos. Immature females or adult males were treated with 5% ethanol for 30 days. After fertilization and mat ing, two-cell embryos, morulae and blastocysts were collected. The PGE synthesis and release were measured by radioimmunoassay. PGE producti on by in vitro derived two-cell embryos from ethanol-treated females w as lower than in the control group (P < 0.01). Also, PGE production wa s reduced when two-cell embryos came from ethanol-treated males (P < 0 .01). There were no differences in PGE synthesis by in vitro derived m orulae and blastocysts in these groups. Two-cell embryos derived from mating produced lower quantities of PGE when they came from ethanol-tr eated females mated with control males, as compared to the control gro up. PGE release by in vivo derived blastocysts from ethanol-treated fe males was reduced significantly, as compared to the control group (P < 0.01). We conclude that a low concentration of ethanol administered c hronically to immature females reduces PGE synthesis and release by tw o-cell embryos from culture in vitro, and by embryos of days 2 and 4 f rom in vivo development.