EXPERIMENTAL DIABETES INSIPIDUS

Abstract

It was shown that in the rat a marked and permanent increase in water-intake and urine-output may be produced by a fine puncture made in the brain-stem near the pituitary gland. The exact place was located in the skull through which a puncture with a scalpel regularly produces a polydipsia and polyuria. Although the effect is permanent, the curve of the increase varies considerably. The maximum increase may be reached on the first day after the puncture, or the increase may be very gradual, so that the maximum is not reached for several months afterwards. The increase in water-intake may be very great. One animal drank almost twice its body-weight each day. The effects produced by these brain-stem punctures are limited to the increase in water-intake and urine-output. There is no increase in food-intake, and body-weight remains unaffected. There are no constant changes in the spontaneous running activity or in the sexual cycles. One animal showed marked loss of hair on the inside of its legs. The absence of changes in the sex cycle suggests that the pituitary gland was not injured in these operations. Evidence is presented which indicates that polydipsia precedes polyuria. The nature and the localization of the lesion in the brain-stem will be described in a later paper.