UBC Theses and Dissertations
Amelioration of experimental hypertension by histidine and ascorbic acid Fitch, Handly Freeman
Hypertension, induced in rats by desoxycorticosterone acetate, has been rapidly ameliorated by the daily feeding of histidine and ascorbic acid. Blood pressures were determined under pentothal sodium by the indirect method using the foot. Desoxycorticosterone acetate (1 mgm/rat) was administered intraperitoneally. Blood pressure elevations obtained in 2 separate experimental runs were nearly identical: an average increase on the 3rd day of 67 mm. of mercury above the pre-injectlon level, followed on the 4th day by a depression back to pre-injection levels, a rise on the 8th day to a maximum increase of 148 mm. and remaining above the hypertensive level from the 6th to the 14th days when daily readings were discontinued. Some of these rats were still hypertensive 27 days after the injection of the desoxycorticosterone acetate. The effect of daily feeding of histidine (20 mgm/rat) and ascorbic acid (75 mgm/rat) on the hypertension produced by desoxycorticosterone acetate indicated that this feeding could maintain the blood pressure below pre-injection levels whether the diet was started before, at the same time as, or after the injection and that the effect became apparent within 24 hours. Another experimental run showed that neither histidine nor ascorbic acid, when used separately, is capable of preventing the hypertension in rats caused by desoxycorticosterone acetate. These results suggest that: (1) the added histidine in the diet Increased the histidine content of the intestinal tract; (2) the decarboxylation of the histidine in the intestinal tract yielded histamine of which the subsequent detoxification by histaminose was inadequate in the presence of the added ascorbic acid; (3) the vasodilatory action of the histamine escaping detoxification effected the reduction of the hypertensive blood pressures.
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