1C,F, 2C-F, 4C). However, CB2 receptor expression was similar between the HF/MCD-Zucker rats and normal-Zucker rats (data not shown). Besides the progressive increase in IHR, acute intraportal infusion of leptin ICG-001 significantly increased endocannabinoid levels in the liver samples collected at the end of perfusion study (Fig. 5A,B). In fact, the number of sticky leukocytes was positively correlated with hepatic endocannabinoid levels in the HF/MCD-Zucker and HF/MCD+leptin-lean rat livers (Fig. 4F). Furthermore, inactivation of Kupffer cells by GdCl3 reduced IHR and endocannabinoid production in the HF/MCD-Zucker and HF/MCD+leptin-lean

rat livers (Fig. 5A,B). Compared with normal-lean rats, increased CYP2E1 activity and protein were found in the HF/MCD-Zucker

rats with hyperleptinemia (Fig. 5C,D). In contrast to the attenuation in leptin-induced increase in IHR and endocannabinoids production, CYP2E1 activity and protein expression were not modified by pretreatment with GdCl3 when Zucker rat livers were examined (Fig. 5C,D). These results indicated that the leptin-induced increase in IHR and endocannabinoids production were independent of hepatic microsomal Romidepsin datasheet CYP2E1 in our NASH rat livers. Paralleling the elevated plasma leptin, an increase in hepatic endothelin-1, ETAR, and activator protein-1 expression were observed in HF/MCD-Zucker rats (Table 1, Figs. 1E, 2E, 3E). In contrast to the other lean rat livers (normal-lean, HF/MCD-lean, and normal+leptin lean rats), an increase in hepatic endothelin-1 levels, activator protein-1, and ETAR mRNAs levels were observed only in HF/MCD+leptin-lean rat livers (Table 1, Figs. 1E, 3E,F). Parvulin However, hepatic ETBR

expression did not differ between the above groups (data not shown). Using the liver perfusion system, it was found that incubation with endothelin-1 significantly increased IHR in all livers (Fig. 5E). Notably, the magnitude of endothelin-1-induced elevation of IHR in the HF/MCD-Zucker and HF/MCD+leptin-lean rat livers were significantly greater than in the normal-lean, normal-Zucker, and HF/MCD-lean rat livers (Fig. 5E). Additionally, the concomitant administration of leptin with endothelin-1 significantly enhanced the endothelin-1-induced increase in IHR of HF/MCD-Zucker and HF/MCD+leptin-lean rat livers (Fig. 5E). Simultaneous preincubation with the ETAR antagonist BQ123 abolished the leptin-enhanced endothelin-1-induced increase in IHR of HF/MCD-Zucker and HF/MCD+leptin-lean rat livers. Nevertheless, concomitant preincubation of the ETBR antagonist (BQ788) with leptin and endothelin-1 did not modify the leptin-induced increased in IHR of the HF/MCD-Zucker and HF/MCD+leptin-lean rat livers. Figure 6A and Supporting Fig. 2A shows that, when compared with a gel exposed to buffer only, incubation of endothelin-1 induced a significant decrease in the collagen gel surface area.