Abstract

V-PYRRO/NO and V-PROLI/NO, two structurally different diazeniumdiolate derivatives were designed as liver-selective pro-drugs, metabolized by cytochrome P450 izoenzymes, with subsequent release of nitric oxide (NO). Yet, their efficacy in the treatment of NAFLD (nonalcoholic fatty liver disease) and their comparative pharmacokinetic and metabolic profiles has not been characterized. The aim of the present work was to compare effects of V-PYRRO/NO and V-PROLI/NO on liver steatosis, glucose tolerance and liver fatty acid composition in C57BL/6J mice fed high fat diet (HFD) as well as to characterize comprehensively ADME profiles of both NO-donors. We demonstrated that despite similar structure, V-PYRRO/NO and V-PROLI/NO differed in their pharmacological efficacy in murine model of NAFLD. V-PYRRO/NO, but not V-PROLI/NO reversed liver steatosis, improved glucose tolerance and favorably modified fatty acid composition in the liver. Both compounds demonstrated rapid absorption after i.p. administration, high clearance values and incomplete bioavailability. However, V-PYRRO/NO was eliminated mainly by the liver, whereas V-PROLI/NO was excreted mostly in unchanged form by the kidney. Both, V-PYRRO/NO and V-PROLI/NO bound to BSA with low binding affinity. V-PYRRO/NO was metabolized by CYP2E1, CYP2C9, CYP1A2 and CYP3A4, while V-PROLI/NO mainly by CYP1A2. Importantly, V-PYRRO/NO was a better NO releaser in vivo and in the isolated perfused liver than V-PROLI/NO what was compatible with the superior anti-steatotic activity of V-PYRRO/NO. In conclusion, V-PYRRO/NO displayed pronounced anti-steatotic effect associated with liver-targeted NO-release, while V-PROLI/NO was not effective, not up-taken by the liver and eliminated mostly unchanged by the kidney.