Circulating molecular variants of growth hormone in childhood

Human growth hormone (hGH) is known to consist of several molecular forms. We examined the molecular nature of circulating hGH in 18 normal children and compared the resulting patterns to those previously obtained in adults. hGH secretion was stimulated with L-dopa, the hormonal forms were extracted from plasma by immunoadsorbent chromatography, and their molecular nature was analyzed by polyacrylamide gel electrophoresis. Circulating monomeric hGH consisted of 73% hGH22K, 16% hGH20K, and 10% of an acidic hGH from (N alpha-acylated or deamidated hGH). These relative proportions are indistinguishable from those found in the plasma of adults. No age or sex differences in the circulating hGH pattern were found. We conclude that the types and proportions of hGH forms in the blood of normal children are the same as those previously established in adults. These data provide a framework against which children with postulated structurally abnormal ("bioinactive") hGH can be compared.