The aim of this study was to investigate the regulation and function of arginine vasopressin (AVP) in pregnant sheep. The mean plasma osmolality of nonpregnant ewes (298 ± 1.0 mosmol/kg, n = 8) was not significantly different from that of late pregnant ewes (295 ± 1.1 mosmol/kg, n = 21). The mean resting plasma [AVP] of nonpregnant ewes (4.1 ± 0.6 pg/ml, n = 8) was not significantly different from that of pregnant ewes (3.3 ± 0.3 pg/ml, n = 21). In a series of dehydration experiments it was established that the slope of the function relating log [AVP] to plasma osmolality for pregnant ewes (n = 13) was not significantly different from the slope of the function relating log [AVP] to plasma osmolality for nonpregnant ewes (n = 4). When AVP was infused into water-loaded ewes, a significant decrease in urinary flow rate and free water clearance occurred at an infusion rate of 0.003 μg/h in both the pregnant (n = 4) and nonpregnant (n = 4) animals. Both groups achieved negative free water clearance at an infusion rate of 0.01 μg/h. These findings suggest that pregnancy does not alter the relationship between plasma osmolality and plasma [AVP] or the renal responsiveness to AVP in sheep.
|Journal||American Journal of Physiology-Renal, Fluid and Electrolyte Physiology|
|Publication status||Published - 8 Oct 1986|