Physiological Concentrations of Growth Hormone Exert Insulin-Like and Insulin Antagonistic Effects on Both Hepatic and Extrahepatic Tissues in Man*

The in vivo conversion of progesterone (Prog) to deoxycorticosterone (DOC) was determined in the circulation of men and women. Labeled Prog was given by constant infusion under steady state conditions, and plasma Prog and DOC were isolated by column, paper, and high pressure liquid chromatographies. Blood production rates (PR) were calculated from the product of the morning plasma concentrations measured by RIA and the MCR. The DOC MCR was determined using data from our previous study. In men, the Prog and DOC levels were 9.8 ± 2.3 (±SE) and 7.8 ± 0.4 ng/dl, respectively. The Prog, MCR averaging the 105 and 120 min samples, was 1968 ± 132 liters/ day, and the PR was 194 ± 46 /μg. The conversion ratio (CR) was 1.3 ± 0.2%, which, taken together with plasma Prog and DOC levels, indicates that less than 2% of plasma DOC was from Prog in blood. Similar data were found in women in the follicular phase. Plasma levels of Prog and DOC were 8.3 ± 1.0 and 6.4 ± 0.6 ng/dl, respectively. The MCR was 1955 liters/day, t...