Preparation and Properties of Growth Hormone from Equine Pituitary Glands

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Abstract
Equine growth hormone has been prepared from acetone-dried residues following extraction of gonadotropins from fresh frozen equine pituitary glands. The growth hormone appeared as a single fraction by gel-filtration on Sephadex G-50 and ultracentrifugation. A sedimentation constant of 3.12 was obtained. Preliminary end-group analysis suggested phenylalanine at both amino- and carboxy-terminals. Amino acid analysis of the growth hormone was performed. Four components of equine growth hormone were separated by polyacrylamide column electrophoresis and all 4 were shown to contain growth hormone activity in hypophysectomized rats. Equine growth hormone which contained 0.9 U/mg by assay in hypophysectomized rats neither increased plasma free fatty acids in man nor showed any effect in man nor showed any effect in a balance study in man. It also failed to react immunologically with antisera to human growth hormone, whole and pepsin-digested bovine growth hormone, and bovine albumin. It contained significant prolactin activity but was essentially free of ACTH, (thyrotrophin) and gonadotropic activity at the dose levels of the assay.