[Transmural flow of D-galactose in the jejunum of young rats using a new perfusion chamber]

The chamber used allows the simultaneous but separated incubation of two intestinal segments (approximately 4 cm in length) in vitro and is especially suited for its application to studies on young animals. Segments are perfused with the help of a peristaltic pump (6 ml/h) without recycling. D-galactose fluxes across rat jejunum have been studied in everted jejunal segments from 19-21 day-old rats. Transmural fluxes (JmsGal) were determined using four external mucosal galactose concentrations (0.2, 2, 10 and 20 mM). The ratios of passive JmsGal were 1 : 11 : 49.7 : 96.7. Those due to active transport of the substrate were 1 : 7.1 : 14.6 : 18.8, indicating saturation. The active component of total JmsGal fluxes was 80%, 72%, 54% and 44%, respectively. Comparison of transmural galactose fluxes in noneverted segments from 20 day-old (suckling) and 25 day-old rats, showed that there is a marked reduction in both passive and active components of substrate flux across the intestine at the time of weaning.