ERYTHROCYTE OSMOTIC RESISTANCE DURING ACUTE HYPOTHERMIA IN AWAKE UNRESTRAINED RATS

Erythrocyte osmotic fragility and plasma ionic composition were studie d in rats subjected to acute hypothermia. A decrease in osmotic fragil ity and a significant increase in plasma magnesium and total phosphoru s were observed in blood from hypothermic rats in relation to control. A decrease in erythrocyte osmotic fragility from hypothermic animals was observed when the test was performed at 37-degrees-C, whereas osmo tic fragility was unaltered if the test was carried out at body temper ature. This could be interpreted as an adaptative response to countera ct the opposite effect on erythrocyte osmotic fragility observed at lo w temperature 'in vitro'.