Abstract
We studied the effect of partial and complete pituitarectomy in rats on the natural resistance to histamine poisoning and correlated the anatomical changes in the suprarenal gland with the variations in resistance. 1 We noted that complete pituitarectomy in rats from 1 to 10 weeks after operation depressed the natural resistance of these animals to histamine poisoning. The M.L.D. was one-fifth to one-third that for normal rats. This decrease in resistance, we found, was associated with involutional changes of the suprarenal gland, such as hemorrhage into or atrophy of the inner zones of the cortex. 2 Rats in which the posterior lobe and a large portion of the anterior lobe were removed showed a similar drop in resistance and atrophic changes in the suprarenal cortex occurred, but where a large fragment of the anterior lobe remained no depression in resistance to histamine occurred and the suprarenal glands were normal. We concluded that the drop in natural resistance following pituitarectomy in the rat is probably secondary to the atrophic changes of the suprarenal cortex induced by the withdrawal of the adrenotropic hormone of the anterior lobe.∗
In the present studies the effect of the repeated injections of suprarenal cortical hormone, in pituitarectomized rats, on the natural resistance of these animals to histamine poisoning was observed.
Eighteen totally pituitarectomized adult albino rats were divided into 2 groups. Ten of these were given, during a period of 6 days, 2 injections daily of cortical hormone in amounts of 1 cc. per rat per day [equivalent to 40 gm. of fresh ox cortex (eschatin, Parke, Davis and Co.)] The interval between pituitarectomy and the day the treatments were begun varied from 5 to 8 days, but in one in stance the rat had been pituitarectomized 89 days prior to the injections of the cortical hormone.
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