Plasma levels and adrenal secretion rates of deoxycorticosterone (DOC) were measured in pregnant and nonpregnant dogs by a double-isotope derivative assay.The removal rates of DOC and aldosterone were also determined following the intravenous injection of these tritiated hormones in pregnant and nonpregnant dogs. Plasma DOC concentrations averaged 2.7 (±1.3 SEM) ng/ml for 4 conscious pregnant dogs compared to 4.3 (±0.7) ng/ml for 6 nonpregnant dogs. The secretion rate of DOC in 3 anesthetized pregnant dogs averaged 377 (±51) ng min compared to 503 ± 78 ng/min for 7 nonpregnant dogs. The differences in plasma DOC concentration and DOC secretion rate in the pregnant and nonpregnant groups were not statistically significant (NS = p > 0.05). In 4 pregnant dogs the plasma half-life (t1/2) for DOC was 24.9 min while the t1/2 for DOC in 5 nonpregnant dogs averaged 20.7 min (NS); the t1/2 for aldosterone in 5 pregnant dogs averaged 21.1 min while in 6 nonpregnant dogs the aldosterone t1/2 averaged 20.3 min (NS). These studies failed to demonstrate an increase in DOC secretion or in the plasma level of DOC with pregnancy in the dog, and failed to show an alteration in the plasma half-life of DOC or aldosterone in the pregnant dog.
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