Comparison of the Acute Metabolic Effects of 22,000-Dalton and 20,000-Dalton Growth Hormone in Human Subjects

Summary

The acute metabolic effects of 20,000-dalton human growth hormone (hGH_20K)in man have not previously been tested. We compared changes in concentrations of free fatty acids (FFA), glucose, and insulin in nine growth hormone deficient children following injection of 22,000-dalton intact human growth hormone (hGH_22K) and the smaller variant, hGH_20K There was a significant decline (37%) in the mean FFA concentration from baseline to œ hour post-injection and from baseline to 1 hour post-injection (36%) in the children given hGH_22K, but no such decline was seen after injection of hGH_20K. No significant differences in mean insulin or glucose concentrations were noted between the two treatment groups, and glucose and insulin concentrations did not acutely change after injection of either hormone.

The results of this study indicate that hGH_20K has a diminished activity for suppression of FFA as compared to hGH_22K. This suggests that GH residues 32-46, missing in hGH_20K, constitute all or part of the region of hGH_22K producing this response, or that the different primary structures of the two hormones result in tertiary structural differences and altered biological activity.

Growth Hormone - 20,000-Dalton Growth Hormone - Free Fatty Acids - Insulin