Abstract
Summary
Experiments on hypophysectomized rats show that exposure to nocuous agents (cold, excessive muscular exercise) induces marked hypoglycemia in the animal before adaptation, but following a few days of pretreatment during the resistant stage, these same agents elicit an inverse reaction and actually increase the blood sugar above the normal level. In the absence of the hypophysis, this acquired adaptation cannot be long maintained, however, and under the influence of continued treatment the animals soon enter into the stage of exhaustion, during which fatal hypoglycemia ensues. In this respect, the response of the hypophysectomized is very similar to that of the adrenalectomized animal. These experiments are not in accord with the assumption that the characteristic disturbance in the carbohydrate metabolism of the hypophysectomized animal is an inability to regenerate blood sugar from endogenous sources, since following adaptation the fasting hypophysectomized animal learns to maintain its blood sugar at the normal, or even above the normal level, although it is exposed to such stimuli (cold, muscular exercise) as cause severe hypoglycemia in the unadapted organism.
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