Biotransformation of a somatostatin analogue in precision-cut liver and kidney slices from rat, dog and man

1. Cleavage of the glucopyranosyl moiety of the somatostatin analogue SDZ CO 611 results in the formation of the major metabolite, SDZ CO 610, in liver and kidney slicesof rat, dog and man, as well as in liver S9 and cytosol of rat and man.2. The rates of SDZ CO 610 formation (nmol/h/mg sliceprotein) for all three species were determined in liver slicesfor 24 h and the relative order was: rat (0.12) > dog (0.096) = man (0.095). The rates of SDZ CO 610 formation (nmol/h/mg sliceprotein) for all three species in kidney were determined, and the relative order was: rat (0.29) > dog (0.16) > man (0.10).3. SDZ CO 610 was rapidly formed by rat gut contents in the absence of NADPH, possibly by disaccharide-splitting enzymes.4. Biotransformation of SDZ CO 611 to SDZ CO 610 in human and rat liver S9 and cytosol was similar to that found in liver slicescultures indicating that cleavage of the glucopyranosyl moiety of SDZ CO 611 could occur in the presence and in the absence of cytochrome P450, possibly by gluco...