Immunologic Studies of Human Growth Hormone

Abstract

The nature of the serum protein contaminant in the human growth hormone preparation of Raben was examined, utilizing the techniques of agar gel diffusion, immunoelectrophoresis and hemagglutination. Human growth hormone antiserum interreacted with Cohn fractions II, IV-4 and V, with a highly purified human serum albumin preparation and with normal human serum. Human growth hormone interreacted with antihuman globulin serum and antialbumin serum. On immunoelectrophoresis, 2 precipitin arcs formed between human growth hormone and the antiglobulin serum. The more intense precipitin line appeared to be related to γ-globulin. The secondary precipitin line corresponded to an area to which the slower moving components of α₁ α₂ and β-globulin migrate. Fractionation of human growth hormone in cross-linked dextran provided 2 distinctly different electrophoretic components. The major antigen and most of the somatotropic activity were associated with the retarded material and suggested that the active component of growth hormone is of relatively low molecular weight. The nature of the nonspecific inhibition of hemagglutination of antigrowth hormone serum was examined and it was determined that this resided in the Cohn fractions IV-1 and IV-4 and in ceruloplasmin, IV-5 and IV-7, subfractions of IV-4. There was an interreaction between the antigrowth hormone serum and a number of crude and highly purified human anterior pituitary preparations. The most striking, reaction was between the antiserum and prolactin.