Serum somatomedin activity depressed after glucagon administration in man.

The variations in serum somatomedin (SM) activity were compared in 14 subjects after glucagon injection (1 mg im), and in 10 controls. A significant decrease in SM activity was observed 30 and 60 min after glucagon (p less than 0.01 to less than 0.001) whereas no significant change was noted in the controls. Analysis of the dose-response curves suggests that this decrease reflects depressed SM concentration. No correlation was found between the variations of growth hormone (GH), cortisol, or fatty acids and those of SM activity. The maximum variations in glycemia, insulin and SM activity occured during the same time interval. These results suggest that glucagon may play some role in the regulation of circulating SM.