The Clearance of Mannitol and Erythritol In Rat Bile.

SummaryIn the rat, as in the guinea pig, dehydrocholate choleresis leads to increased excretion of mannitol and erythritol, but in the rat the amounts of the solutes appearing in bile are greater. This difference is much more pronounced for the larger solute, mannitol. For mannitol, but not for erythritol, the rate of change of clearance following dehydrocholate is also greater in the rat. Unlike its effect in the guinea pig, secretin produces only a trivial choleresis in the rat. Despite a previous report that mannitol is concentrated in rat bile, bile: plasma concentration ratios greater than unity were not observed in the present studies for either mannitol or erythritol. In both the rat and the guinea pig the extracellular fluid volume of skeletal muscle as estimated from the plasma equivalent tissue space of mannitol is twice as large for muscle from the abdominal wall as for gastrocnemius. The discrepancy is attributed to differences in connective tissue content.