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The effects of intra-amniotic administration of 1-desamino-8-D-arginine-vasopressin (DDAVP) at 14 days of embryogenesis on movement asymmetry in neonatal and mature mongrel white rats were studied. Controls consisted of intact and sham-operated animals, as well as rats given intra-amniotic saline. The population profile of asymmetry was assessed in terms of the tail position of rats aged two days, and also in terms of the direction of excursions in a T-maze in three-months males. The proportion of animals showing asymmetrical tail poses was no more than 36% in controls; the ratio of left-asymmetrical and right-asymmetrical intact rats was 2:1. DDAVP increased the number of rats with asymmetrical tail poses by a factor of 1.5-2.6, and right-asymmetrical individuals became predominant. This effect was demonstrated graphically as a bell-shaped dose-response curve with a peak response at doses of 3 x 10(-8) and 3 x 10(-6) mg. The selection probability for the right-hand side of the maze in experimental animals was 0.71 +/- 0.06, which was significantly higher than in animals of the three control groups, which showed no preference for the direction of excursions. These results indicate lateralization of the action of DDAVP in the developing central nervous system, leading to a predominance of right-sided motor responses in neonatal and mature rats.

The effect of alimentary administration of silver salts upon embryogenesis in rats was studied. Feeding of female rats throughout the term on a regular diet supplemented with AgCl did not cause alterations of their physiological functions, despite the fact that enzymatically active copper-containing ceruloplasmin (CP) was eliminated from the blood plasma. However, developmental abnormalities of embryos, their prenatal death or the 100% mortality of the newborns in the first 24 h of life was seen. Copper content in placenta and fetal tissues was strongly diminished. Cu, Zn-superoxide dismutase (SOD) activity decreased in cytoplasm of embryonic cells along with a drop, though less pronounced, in the tissues of the pregnant females. Embryotoxicity of AgCl was seriously diminished by repetitive injections of native CP to the pregnant rats. Such treatment resulted in an increase of SOD activity in placenta and embryonic tissues. The mortality of the newborns also became less. It is suggested that the embryotoxic effect of AgCl is caused by its ability to interfere with copper metabolism, in particular by altering the copper-transporting function of CP.