THE EFFECT OF GROWTH HORMONE ON HEPATIC CATALASE, AND ON CELL VOLUME AND HEMOGLOBIN CONTENT OF BLOOD IN RATS1

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Abstract
Under stated exptl. conditions, concns. of hepatic catalase in hypophysectomized immature female Sprague-Dawley rats were 2-3 times as great as in normal pair-fed controls. This difference was not due to diminution of the enzyme in the normal groups as a consequence of restricted food intake, for it was also observed when hypophysectomized animals were compared with normals fed ad lib. Injn. of a fairly pure growth hormone prepn. in doses of 20 [mu]g./animal/day for 10 days did not markedly lower the high hepatic catalase of 5 operated animals. In other operated groups hepatic catalase values were reduced to or maintained at normal levels by treatment for 17-24 days with a less purified growth hormone prepn., in doses 20 times greater in potency and 50 times greater in wt. than those of the purer prepn. Similar large doses produced more variable, though at times significant, small decreases of hepatic catalase in normal young and adult animals. Treatment with growth hormone had a slight tendency to reduce hemoglobin concn. of the blood normal and hypophysectomized rats. It would appear that lack of growth hormone is not an important causative factor in the anemia of hypophysectomy, the occurrence of which is again confirmed. The rise in hepatic catalase during development of this anemia suggests the possibility of a reciprocal relationship between heme-containing proteins. Growth hormone prepns. do not accelerate protein synthesis in general, since the concns. of some enzymes are increased, while others are unaffected or decreased.