Growth hormone-like material in normal human tissues

Abstract

We report herein the presence of extractable levels of immunoassayable (RIA) and receptor-assayable human GH (hGH)-like material in normal human liver, kidney, lung, striated muscle, colon, stomach, and brain. Levels of hGH by RIA were the highest in the liver (mean, 14.7 ng/g), followed by those in the kidney (mean, 11.3 ng/g) and lung (mean, 4.6 ng/g), but small amounts were detected in at least some specimens of all types of tissue. This material eluted in the region of monomeric pituitary hGH on Sephadex G-100 chromatography and showed parallelism in a RIA to pituitary hGH on log-logit plots of dose-response lines. Passage of the material through an anti-hGH immunocolumn greatly reduced its immunoreactivity. Assay of eight sets of extracts by receptor assay using a male rat liver membrane preparation showed the GH-like substance to have a receptor to immunoassay potency ratio of 3.8:1 relative to monomeric hGH standard. Scrupulous correction for acidity, osmolality, and possible protein and enzyme effects and extraction of the hGH-like material by immunoabsorption excluded the possibility of artifacts causing the appearance of hGH-like material in the extracts.