BIOASSAY OF THE GROWTH HORMONE OF THE ANTERIOR PITUITARY1

Abstract

EVIDENCE HAS BEEN ACCUMULATING in favor of the concept that the growth hormone of the anterior lobe of the pituitary is a separate entity, different from the well established pituitary hormones such as the gonadotropic, lactogenic, thyrotropic and adrenocorticotropic hormones (1, 2). Final proof for the individuality of the growth hormone, however, will only be possible when the active principle is obtained in chemically pure form. For the purification of such a biologically active substance, a satisfactory method of assay is necessary, and the efficiency and specificity of the method is of primary importance. There are difficulties, however, in finding a specific and reliable test object for a hormone that controls a phenomenon as complex as somatic growth. The use of gain in body weight of rats for the determination of the growth hormone potency of pituitary extracts was first described by Evans, et al. (3), and is still being used for assay of growth hormone preparations by almost every investigator in...