RADIOIMMUNOASSAY OF HUMAN GROWTH HORMONE IN SERUM

A radioimmunoassay of human growth hormone （HGH） in serum is described. The standard curve of Logit B/B₀ was shown as a straight line.The recoveries were 106.7,95.3,94.9 and 90.4 percent for 2.5,5,10 and 40ng/ml of the added HGH standard in serum,respectively.The intraassay variation were 6.8 and 8.5 percent for 3.5 and 26.7ng/ml of patients’ sera,and the interassay variation,17.9 and 7.7 perc- ent for 5.3 and 29.2ng/ml of pooled sera,respectively.The sensitivity was 0.2ng/ml. The antibody had a cross reactivity of 2% with HPRL,and none with HTSH or HCG. In normal adults （10 males and 10 famales）,the basal HGH levels were under 3ng/ ml,but the ambulatory HGH levels varied from undetectable level to 4.8ng/ml in men or to 28ng/ml in women.After intravenous injection of insulin （0.1U/kg）,the HGH levels were elevated in all subjects from the basal levels to more than 15ng/ml at the peak.Following 100g oral glucose,the HGH levels were suppressed from ambulatory levels to＜2ng/ml in men or to＜3ng/ml in women at the nadir.In 4 cases of pituitary dwarfism,the basal HGH levels were below 2ng/ml,but not responsive to insulin injec- tion.In 3 patients with acromegaly,the basal HGH levels ranged from 9—90ng/ml, and elevated levels were not suppressed by oral glucose.