A sensitive method for detection of circulating forms of human growth hormone by immunoautoradiography.

Several different forms of hGH have been isolated from the pituitary, but little is known about modifications of synthesized forms that may exist in the circulation. We used a combination of serum immunoextraction with gel electrophoresis and electrophoretic blotting to detect circulating hGH isohormones. Three different components were identified, with the predominant form being 22,000 MW isomer. The method is sensitive to nanogram quantities of hGH and is applicable to the screening of human serum for the presence of variants of hGH.