GROWTH IN THE YOUNG HYPOPHYSECTOMIZED GUINEA-PIG

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Abstract
SUMMARY: 1. Following hypophysectomy, young female guinea-pigs showed an initial fall in body weight followed by a steady increase for many months, although the mean growth curve never reached that of intact guinea-pigs. There was proportionately more growth in length than in body weight. 2. After hypophysectomy the adrenal glands did not increase in weight when the animals grew. The concentration of ascorbic acid in the adrenals was unchanged by hypophysectomy. 3. After hypophysectomy the thyroid glands showed a smaller increase in weight than in intact guinea-pigs. 4. Closure of the epiphyses was usually delayed by hypophysectomy. 5. In relation to body weight the abdominal fat pads were smaller in hypophysectomized than in intact guinea-pigs. The carcass contained a slightly increased percentage of total nitrogen but the percentages of fat and carbohydrate were not significantly different from those of intact guinea-pigs. 6. Although the absolute weights of the livers were less in hypophysectomized guinea-pigs compared with intact ones, their relative weights were the same. Hypophysectomy resulted in an increased percentage in the fat content of the liver, and no change in the percentages of carbohydrate or total nitrogen. 7. Hypophysectomized guinea-pigs showed insulin hypersensitivity for at least 5 weeks after operation, although it was reduced by the administration of cortisol. Three months after hypophysectomy this increased sensitivity was lost.