| Popis: |
The effect of peptide hormones and other small intestinal secretory stimulants on ion and water transport by ascending and descending rat colon was investigated in vitro using a muscle-stripped everted open sac preparation. Net water flux was measured gravimetrically at 30min intervals for 150 min, each sac serving as its own control. Water flux rate was constant over the entire period and equal in ascending (15.6 ± 1.1) and descending (14.9 ± 1.1 μl hr-1 mg-1 of dry weight) colon. Both segments responded identically to all test substances. Neither glucagon 10-5 m nor pentagastrin 10-5 m, singly or in combination, had a significant effect on net water flux. In contrast, theophylline 10-2 M and dibutyryl cyclic AMP 10-3 M reduced net flux significantly by 23% (P |
