No abstract

We have previously determined the optimal conditions for H 0 and Na absorption by the jejunum of the normal and tissue A g e d rat using various f o m l a e of oral hydration solutions (OHS). H 0 absorption was inversely pmprtional to omlality and Na &sorption was directly proportional to its concentration. In the present study we investigated the characteristics of exper-tal hydration in an animal &el of P m . This was achieved with a low protein (4%), reduced carbohydrate diet fed to juvenile rats for 3 weeks. Absorption was assessed by an in vivo perfusion procedure using an OHS with (in mEq/l) 60 Na, --0 K, 50 C1, 30 HCO and 111 Wl glucose (Glu). Phenol red and ' H 0 were used as Akers. The net H 0 fluxes in PEM (M) rats we& lower than in controls (C) (1.7$*0.10 vs 3.11f0.06 pl/min x an, Pc0.001). This difference was due both to a decrease in the mcosa-to-serosa influx of H 0 in M rats (M= 5.99f0.16; C= 6.43f0.14, Pc0.05) as w 1 1 as to2a greater efflux of fluid (M= 4.22*0.12; C; 3.52*0.13, P<0.001). PBl also resulted in failure to absorb Na from that type of 011s (M= -1.4k5.2; C= 52.2f9.4 nEq/min x an, P