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Absorption Of Caffeine Through Isolated Rat Small Intestine, William James Hatch
Absorption Of Caffeine Through Isolated Rat Small Intestine, William James Hatch
Theses and Dissertations
Intestines of fifty-six albino rats of the Holtzman strain were removed and perfused with Krebs bicarbonate buffered solutions containing caffeine. After one hour of absorbtion, caffeine was extracted from the serosal fluids in chloroform and concentrations were determined spectrophotometrically. It was found that all portions of the small intestine transported caffeine against a concentration gradient. This transport mechanism demonstrated saturation kinetics and was inhibited by ouabain. It was concluded that the movement of caffeine from the mucosa to the serosa of the small intestine cannot be the result of simple diffusion. Possible mechanisms by which the absorption of caffeine takes …
Hepatic Ornithine Metabolism In Hydrazine-Treated Rats, Van Saxton Hubbard
Hepatic Ornithine Metabolism In Hydrazine-Treated Rats, Van Saxton Hubbard
Theses and Dissertations
Ornithine plays an important role in mammalian intermediary metabolism. Ornithine can be (1) utilized as a component of the urea cycle, (2) decarboxylated to form putrescine, a precursor of the polyamines, spermidine and spermine, and (3) converted metabolically to arginine, proline and glutamate. In prior investigations conducted in our laboratories and others, free endogenous hepatic pools of ornithine were found to be elevated following hydrazine administration. Consequently, time-course alterations of arginase, ornithine δ-transaminase, ornithine transcarbamylase, and ornithine decarboxylase activities were investigated regarding the effect of hydrazine treatment on hepatic ornithine metabolism in the rat. As an outgrowth of these investigations, …