BIOCHEMICAL RESPONSE TO INFECTION.
Final technical rept. 1 Jul 64-30 Jun 66,
NOTRE DAME UNIV IN
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A study was conducted on the biochemical regulation of anti-microbial defense potential. Histamine, 5 hydroxytryptamine, vasculoactive peptides, adrenal corticosteroids and certain vitamins were included. Results indicate that the rat contains two major histidine-decarboxylating systems. A fast acting system is found in the stomach and produces more histamine than any other internal organ. Throughout the length of the small intestine lower levels of histidine decarboxylase consistently produce small amounts of histamine. Because of the amount of tissue involved, this constitutes the second major internal histamine producing system. Levels of histamine and also of 5-hydroxytryptamine in the small intestine are affected by the composition of the intestinal microflora, presumably via effect on both formation and degradation. Rats contain approximately 1ng of bradykinin equivalent of carboxypeptidase sensitive vasculoactive per ml. The wall of the small intestine contains about 3 nggram. Monoassociation of germfree rats with Salmonella typhimurium Lobund no. 750A resulted in severe stress, but the intensity of the association syndrome depended to a great extent on the composition of the complete diet. Surviving animals showed an adequate cellular and humoral immune response, and a 50 to 100 fold increase of carbon clearance rate over conventional values. Histamine and 5-hydroxytryptamine values in the small intestine showed a transitory decrease which roughly paralleled the condition of the animal as depicted by body weight and general appearance. A definite increase in requirements for thiamine and ascorbic acid during the first 10 days of monoassociation was indicated.
- Medicine and Medical Research