Insulinhypoglycemia but not Arginine Infusion Stimulates Circulating Plasma Growth Hormone-Releasing Hormone (GHRH) Concentrations in Children

Summary

The effect of insulinhypoglycemia and arginine infusion on circulating concentrations of plasma growth hormone-releasing hormone (GHRH) and growth hormone (GH) has been studied in 24 children (4.4 to 14.3 years). Plasma GH and GHRH concentrations were determined by RIA. Basal plasma GHRH levels were detectable in the plasma of all patients ranging from 6.8 to 27.1 pg/ml. Injection of 0.1 U/kg body wt. insulin i.v. resulted in an increase of plasma GHRH levels (11.1±1.4 pg/ml vs. 18.8±2.6 pg/ml; P < 0.01) preceding that of plasma GH (1.5±0.4 ng/ml vs. 13.6±1.3 ng/ml; P < 0.01). Infusion of 0.5gm/kg body wt. arginine hydrochloride did increase GH concentrations (2.0±0.6 ng/ml vs. 13.9±2.3 ng/ml; P < 0.01) but did not change circulating plasma GHRH levels. Since the source of peripheral GHRH concentrations is not known the importance of these findings remains to be determined.

Key-Words

Growth Hormone-Releasing Hormone - Growth Hormone - Insulinhypoglycemia - Arginine Infusion