Heterogeneity of Growth Hormone in the Nocturnal Serum of Children

Abstract

ABSTRACT. The nocturnal serum of 13 nongrowth hormone deficient, hyposomatomedinemic short children and of 12 normal children of average height was analyzed by both polyclonal and biclonal radioimmunoassays. The biclonal/polyclonal ratio for immunochemical grade human growth hormone was 1.0, but for the nocturnal sera in both groups, this ratio was significantly less than 1.0 (range 0.5-1.2, average 0.7-0.8). The ratio did not differ significantly between the two groups of children. (Pediatr Res 19: 981-985,1985) Abbreviations RIA, radioimmunoassay GH, growth hormone hPL, human placental lactogen hPRL, human prolactin hTSH, human thyroid-stimulating hormone hFSH, human follicle-stimulating hormone hLH, human luteinizing hormone hGH, human growth hormone RRA, radioreceptor assayThe purpose of this study was to compare the RIA profile of the endogenous GH between normal children of average height and hyposomatomedinemic non-GHD, short children identified in a preceding investigation (I) by means of newly available monoclonal RIA techniques (2) together with the conventional polyclonal assay (3). The gel-filtration behavior of the serum GH also was compared between the two groups of children. METHODS SUBJECTSThe normal group comprised six boys and six girls, 12 to 18 yr old, between the 5th and 95th percentiles in height. History and physical examination revealed no evidence of acute or chronic illness.The hyposomatomedinemic, non-GHD, short (less than third percentile) children consisted of 10 boys and three girls, 7 to 10 yr of age, who had been identified during phase 2 of a preceding study (1). Their clinical characteristics are summarized in Table 2 of the preceding report (1). Mean serum immunoreactive GH2 response to L-dopa or glucagon was > 12 ng/ml, showing normal immunoreactive GH status. STUDY DESIGNThe children were hospitalized for 5 days. They received no medications. The short children had not received hGH injections during the previous month. Their diet was 2300 calories, 100 g protein, 250 g carbohydrate, and 100 g fat. Via an inwelling heparin lock inserted at 2000-2 100,5 ml heparinized blood were removed on retiring, and at 30, 60, 90, and 120 min after sleep began. The blood was kept at 4" C until 800, when it was spun; the serum was stored at -20" C for up to 2 wk before analysis by RIA (4). Some sera also were examined by gel filtration. MATERIALSThe kits were obtained from Kallestad Laboratories (New York, NY) ("polyclonal kit") and from Hybritech Laboratories (Los Angeles, CA) ("biclonal kit"). Two mouse monoclonal antibodies (33.2 and 101.3) to hGH were purchased from Hybritech. According to the manufacturers, the antibodies were directed at different epitopes of the hGH molecule. The precipitating antibody (rabbit antiserum to mouse IgG) was obtained from Calbiochem-Behring (Los Angeles, CA). The labeled hGH used in the monoclonal assays was obtained from Kallestad Laboratories. Immunochemical grade hGH, used as the cold hormone in these assays, was from National Institutes of Health,...

Sarcopenia: Aging-Related Loss of Muscle Mass and Function

“…As discussed above, other factors than quantitative changes related to total muscle fiber number and muscle fiber size may play a significant role for the aging-related decline in muscle force. A significant dissociation between muscle mass and strength have been reported during aging, hormone treatment, exercise, and inactivity [reviewed in (780)] and was suggested to be secondary to central factors rather muscle specific changes (780). Central factors may play a significant role for aging-related changes in motor function, but as mentioned above, factors distal to depolarization of the muscle membrane are the primary determinants underlying the impaired capacity to correct an impending fall in old age with consequences for falls and fall-related injuries (809).…”

Properties of a cleaved two‐chain form of recombinant human growth hormone

“…Lewis et al (2) have proposed that the wide range of responses of various tissues to stimulation by growth hormone may be the result of such cleavages. There is experimental data that the two-chain variant of growth hormone has potentiated growth-promoting properties and is formed in vivo as a post-translational event (13,14).…”

The Short Child with Subnormal Plasma Somatomedin C

“…A second possibility is a failure of nocturnal secretion of hGH as described by Wise et al (9); this has been ruled out by the nocturnal serum GH data (10). Other causes cannot be excluded: Impaired hepatic production of SmC; nutritional disorders (1 1); abnormally rapid clearance of SmC; an altered SmC binding system (12); or a bioinactive GH (3-5) are possible, but are generally outside the scope of the present data.…”

“…Average weight was appropriate for height (Table 2), tending to rule out severe malnutrition. The possibility of a bioinactive GH is considered in the accompanying report (10).…”