Alterations in glucose turnover following single intravenous injections of epinephrine and glucagon in dogs.

The technique of priming injection-continuous infusion of tracer glucose-U-C14 was employed in 7 anesthetized dogs, each serving as its own control, to determine the immediate changes in rates of appearance (Ra) and disappearance (Rd) of plasma glucose following single intravenous injections of epinepbrine (IO pg. per Kg.) and glucagon (I pg. per Kg.). Mean maximal hyperglycemia induced by the hormones was comparable in magnitude, but it was achieved in 4 minutes after epinephrine injection compared with 8 to 10 minutes after glucagon. Furthermore, Ra was increased 5to ‘I-fold during the first 4 minutes following epinephrine injection and subsequently fell to below control levels for about 30 minutes. In contrast, following glucagon, Ra was increased 3to 4-fold during the first 8 minutes after injection with subsequent return to control levels. After both epinephrine and glucagon, Rd increased 1.5to a-fold during the first 10 minutes; it returned to control levels IO minutes after epinephrine and 30 minutes after glucagon. These data indicate that the increment in plasma glucose results from enhanced hepatic glycogenolysis. However, contrary to the suggestion of others, the effect of epinephrine on the liver does not appear to be mediated via glucagon release. (Metabolism 17: No. 7, July, 631-637, 1968)