Horseradish peroxidase transport across rabbit jejunum and Peyer's patches in vitro.

Uptake and transport of horseradish peroxidase (HRP) have been observed in both Peyer's patches (PP) and jejunal epithelium (JE), and the quantities transported across each tissue were compared. Steady-state was reached much faster in PP than in JE. In Ringer solution, no significant difference was found between the HRP fluxes conveyed through PP and JE. In the presence of 10 mM glucose, slight net secretion was observed in JE but not in PP. In both tissues, the transport mechanism was shown to be sensitive to metabolic inhibitors. By contrast, in PP, ammonia did not significantly enhance intact HRP fluxes. Intracellular transfer and catabolism were estimated by measuring transepithelial fluxes of tritiated HRP. In PP, fluxes from mucosa to serosa and from serosa to mucosa were both greatly reduced (9.18 +/- 3.9 and 10.5 +/- 5.1 pmol X h-1 X cm-2, respectively) compared with JE (106.02 +/- 16 and 31.3 +/- 9.3). These results indicate that intact HRP fluxes are similar in PP and JE, but that tritiated HRP fluxes (intact plus degraded HRP fluxes) are smaller in PP. Together, these results suggest that the specific characteristics of HRP transport across PP are fast uptake and reduced degradation.