IMMUNOCHEMICAL STUDIES ON THE HETEROGENEITY OF HUMAN GROWTH HORMONE (HGH)

Abstract

ABSTRACT The specific antigenic patterns of human growth hormone in various human pituitary extracts were determined by analysis in gel filtration, in starch gel and agar gel immunoelectrophoresis. The analysis of pituitary extracts by gel filtration on Sephadex G-200 indicates that HGH complexes with different molecular weights were present in all tested pituitary extracts. The rate of formation of high molecular HGH was dependent on the extraction procedure used. Altogether seven immunologically active components of HGH were detected by analysis of crude pituitary extracts in starch gel immunoelectrophoresis. The number and the rate of formed HGH components were dependent on the solvent used for the extraction of pituitary homogenates and on the sequence of extraction procedures. The electrophoretical patterns obtained were reproducible. The electrophoretical behaviour of HGH of various pituitary extracts in agar gel also suggested the presence of multiple components. Three different positions were observed between the α1- and β1-globulins. The analysis of pituitary extracts in the two dimensional double diffusion technique in agar gel using an absorbed anti-HGH-serum gave evidence of the antigenic homogeneity of HGH in the different preparations. It is concluded that the electrophoretic heterogeneity of pituitary growth hormone preparations is already determined by the first step of the extraction.