Effect of pyrithioxine (Encephabol) on growth and exploratory behaviour of rats malnourished in early life

Effects of pyrithioxine (Encephabol Merck) on growth, mortality and exploratory activity were studied in groups of rats kept on a low protein (LP) diet from birth to day 42 of life. In the first experiment pyrithioxine (40 mg/kg b.w.) was administered i.p. from day 35 to day 48, in the second experiment from day 100 to day 115.Pyrithioxine given to young rats by injection reduced mortality during protein deprivation and during the first weeks of nutritional rehabilitation as compared with malnourished rats injected with NaCl solution. Between days 90 and 140 better growth was recorded in the LP group treated with pyrithioxine. Pyrithioxine normalized behavioral symptoms of early malnutrition both during the period of deprivation and after realimentation. On day 150 of life these rats did not differ behaviorally from the well nourished group.Pyrithioxine injected in adult age did not affect the body weight of the LP group, and its the favorable effect on exploratory activity was transient. In normal rats pyrithioxine did not influence growth or behavior either in the first or in the second experiment.Presented in part at the annual Psychopharmacological meeting, Jeseník Spa, January 1971 (Fraková and Beneová, 1971).