[Interferences between nutrients in their absorption from the peritoneal cavity in rats]. / Interferencias entre nutrientes en su absorción desde la cavidad peritoneal de ratas.

With the aim of detecting possible interferences in the absorption of glucose, amino acids and fats we infused several combination of them into the peritoneal cavity of the Wistar rats. After intraperitoneal infusion of 2 mu Ci-L-glucose-C14 with 5 ml of D-glucose 5 per 100 and L-glucose-C14 with 5 ml of "16N" 3.5 per 100 in different groups of animals, we detected slight differences in plasma radioactivity one hour after infusion. We also found moderated differences in plasma radioactivity among the groups of animals infused with 1 mu Ci of fat radioactive amino acids plus 5 ml of D-glucose 5 per 100 and in the group infused with 1 mu Ci of 5-L-amino acid-C14 plus 5 ml of "16N" 3.5 per 100, after four hours of the infusion. We found no differences among those groups of animals infused with fat plus glucose and with fat plus amino acid with respect to those infused with fat alone. In summary, as glucose and amino acid absorption pathway are the same (capillary flow) seem reasonable that they interfere with each other when they are infused intraperitoneally. Fat infusion that not seem to interfere with other substrates possible due to the different absorption pathway (lymphatic channels) but further studies are needed to determine this.

[Nutrient absorption rate from the peritoneal cavity in rats]. / Velocidad de absorción de nutrientes desde la cavidad peritoneal de ratas.

A study has been done of the absorption/elimination kinetics of nutritive substances such as glucose, amino acids and fats from the peritoneal cavity. For this purpose, 48 male Wistar rats were administered an intravenous or intraperitoneal "bolus" of 2 microCi of L-glucose-C14/250 g of body weight, 3 microCi of D-alanine-L-C14/250 g and 0.4 g of Intralipid/250 g body weight. A two-compartment pharmacokinetic model was applied to determine the absorption, elimination and distribution constants among the different body compartments of each of these substrates, as well as the absorption and elimination halflife. When the areas under the curves were compared following intravenous and intraperitoneal infusion, the total physiological availability or fraction of dose absorbed over a given period of time were calculated. A higher absorption and elimination constant for glucose and amino acids as compared to fats was found. Higher than 90% absorption for all substrates was found, but since in the case of fats the elimination constant is lower and longer the elimination halflife, we must be cautious regarding its infusion rate.