EXPERIMENTAL STUDIES ON VITAMINE C. ABSORPTION (Part 1.)

Abstract

Vital phenomena of the intestinal membrane cells play an important part in the absorptive mechanism of the intestines, besides physicochemical functions such as diffusibility and osmosis. The absorption of substances such as NaCl and Glucose is allegedly belong to the former category. Concerning the absorption of vitamine C (abbrev. v-c), the author has endeavoured to experimentally clarify a) to which of the two categories v-c enters, and b) following absorption, to what extent v-c is increased in blood and urine.
Experimental procedures: Absorption coefficient and intramucous absorption were analysed by injecting v-c dissolved in normal saline into a blind canal made by surgically ligating a definite length of rabbit intestine. Rise and fall of v-c in plasma and urine were assayed by injecting v-c solutions into intestinals tracts, on which no ligations were performed. The quantities of v-c in plasma and urine up to 2 and 6 hours respectively were analysed. Tests were performed on 32 rabbits.
Absorption was most rernarkarble in the jejunocecal region, i. e. within 1 hour after injection, 41% of the v-c was absorbed, while in the duodenum hardly no absorption was observed. Absorption of v-c was not parallel with the amount administered, and increase in absorption coefficient, intramucous absorption, and plasma concentration were all slight as compared to increase in administration. In other words, absorption of v-c is caused by the vital functions of the cells of the intestinal mucous membrane, and not merely by diffusibility. Plasma concentration of v-c after 1 hour was still under 1mg%, but continued to rise, and when exceeding 1mg% its urinary excretion showed a marked increase.