Some immunological properties of rabbit antiserum to mouse growth hormone.

As a fundamental experiment for the study on the role of growth hormone in mouse mammary gland, some immunological properties of rabbit antiserum to mouse growth hormone (MGH) were studied. Antiserum was obtained by immunizing New Zealand White male rabbits with MGH preparation extracted from mouse anterior pituitaries. The precipitin titer of the antiserum by precipitin ring test against MGH preparation was 1: 16. The antiserum did not react with mouse serum, and extracts of brain, liver, kidney, spleen and heart. The immunoelectrophoretic pattern of polyacrylamide gel after electrophoresis of anterior pituitary with the antiserum or the reaction of antiserum with MGH and mouse prolactin (MPL) preparations on the Ouchterlony agar plate showed two precipitin arcs or lines; one appeared to be due to MGH and another due to MPL. The absorption of the antiserum with MPL preparation resulted in the development of a single precipitin line between the absorbed antiserum and MGH preparation on the Ouchterlony agar plate. Further, immunoelectrophoretic pattern of polyacrylamide gel after electrophoresis of mouse pituitary homogenate with the absorbed antiserum showed one precipitin arc at the corresponding site of MGH band. Inhibition by the antiserum of the biological activity of MGH was proven in rat tibia test and in body and mammary growth of a mouse. All the results have demonstrated that the antiserum absorbed with MPL preparation is specific only to MGH.