In Vivo Transport of Water and Electrolytes in the Infant Rat Small Intestine 1

Summary

Using an in vivo onepass perfusion technique, transport of water (H₂O), sodium (Na), chloride (Cl), bicarbonate (HCO₃) and potassium (K) was studied in segments of the jejunum and ileum in normally growing 2-, 3- and 8-week-old rats. From solutions containing in mmole/1, NaCl 120, KCl 5, NaHCO₃ 25, Phenol Red 100 μmoles, glucose 0 or 15 and mannitol 25 or 10, quantitative differences in the net transport rates (μmoles/hr per g dry weight of segment) were observed. In general permeability of the epithelium of the perfused segments to H₂O, Cl, HCO₃ and K appeared to be greater in the 2 than in the 8-week-old rats. Glucose had the expected effect of enhancing absorption rates of water and Na in the segments of the rats at all three age periods.