Abstract
von Hann, 1 on the basis of pathological material, suspected that a functional pars anterior of the hypophysis was essential for a deficiency in the antidiuretic principle to be evident in the form of d.i. This contention has been championed particularly by Richter 2 and Ingram and Fisher 3 on the basis of experimental material. The experiments reported below reinforce data already on record, 4 which demonstrate that a moderate d.i. can obtain in the total absence of the pars anterior.
The water exchange was followed in 8 adult dogs for 6 months or longer after total hypophysectomy. Total hypophysectomy was made certain at operation by deliberate encroachment upon the ventral hypothalamus and cauterization of the base of the pituitary fossa. The dogs were maintained on a constant daily food intake, 50 g of baloration per kilo of body weight per day. Water was available to them 22 hours of each 24. The food given and water drunk was calculated for the duration of the experiments on the basis of the operation weight, which ranged from 6 to 10 kilo.
Without exception, there was a decided increase in the water exchange following operation which persisted indefinitely (10 months). In some instances the increase was immediate with no subsequent tendency to a “latent period”. In other instances the rise occurred progressively over a period of several days. Usually the polydipsia was maintained at a higher level during the immediate 2-3 weeks after operation than it was in the final stationary state (after 3 to 6 weeks). The magnitude of the polydipsia present in the final state varied among the animals from 150 to 350 cc per kilo per day, the mean being around 300 cc. The preoperative water intake was in the neighborhood of 50 cc per kilo per day. There was always a corresponding plyuria of like magnitude, the urine being sugarfree and of low specific gravity.
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