The influence of micelle formation on XXXX secretion.

@entity2226 @entity7362 @entity6041 @entity29677 @entity235 @entity6741 @entity25987 @entity3645
1. The influence of micelle formation on @entity6741 secretion was assessed by analysing the secretory characteristics of, and interaction between, the natural micelle-forming @entity3645 , @entity7362 and @entity6041 , and the artificial non-micelle-forming @entity3645 , @entity29677 and @entity25987 (both of which are subjected to reductive metabolism), in anaesthetized @entity235 . 2. Competitive secretory interaction between these two classes of @entity6741 was demonstrated thereby indicating that they share the same biliary transport system. @entity29677 had a lower affinity for the transport system than that of @entity7362 and the metabolic derivatives of @entity25987 . 3. The (initially determined) biliary secretory maxima for @entity29677 (4 . 9 +/- 1 . 9 (S.D.) mumole/min. kg, n = 6) and total ' @entity25987 ' in @entity2226 replete @entity235 (4 . 2 +/- 1 . 0 mumole/min. kg, n = 16) were both significantly less than those for @entity7362 (8 . 0 +/- 1 . 8 mumole/min. kg, n = 16) and total @entity6041 in @entity2226 replete @entity235 (6 . 9 +/- 1 . 2 mumole/min. kg, n = 12). 4. The initially determined secretory maxima of @entity29677 and ' @entity25987 ' were elevated by about 30 and 36%, respectively, by an earlier period of @entity7362 administration; the most likely explanation (which is supported by independent morphological studies) for this effect is that @entity7362 increases the number of functional 'carriers' in the canalicular membrane. When calculated for optimal conditions, the secretory maxima of the non-micelle-forming @entity3645 closely approached those of the micelle formers. 5. The above results would seem to indicate that micelle formation (in the hepatocyte, canalicular membrane or bile) is not essential for the effective translocation of @entity6741 by the specific canalicular membrane receptors. The results also suggest that the effective concentration of @entity6741 in bile (possibly 60--70 times greater in the case of the non-micelle-formers) is not an important determinant of the net secretory performance of conjugated @entity6741 . 6. At the same @entity6741 secretion rate (3 . 06 mumole/min. kg), the bile flow rate associated with @entity29677 (44 . 3 +/- 2 . 7 (S.D. along regression line) microliter/min. kg, n = 38) was significantly greater than that associated with @entity7362 (29 . 5 +/- 7 . 7 microliter/min. kg, n = 80) but significantly less than that associated with ' @entity25987 ' in @entity2226 replete @entity235 (51 . 7 +/- 4 . 8 microliter./min. kg, n = 33), ' @entity25987 ' after acute @entity2226 depletion (61 . 2 microliter./min. kg, n = 1) and free @entity6041 after @entity2226 depletion (49 . 8 +/- 9 . 8 microliter/min. kg, n = 92). The extra flow associated with the free @entity3645 is derived by means that are largely or entirely independent of their osmotic activity in bile.
