Severe diabetes and leptin resistance cause differential hepatic and renal transporter expression in mice

Transporter mRNA and protein expression were quantified in livers and kidneys of adult C57BKS and db/db mice, which have a severe diabetes phenotype due to a lack of a functional leptin receptor. The urinary excretion of acetaminophen-glucuronide, a substrate for multidrug resistance-associated proteins transporters was also determined. The mRNA expression of major uptake transporters, such as organic anion transporting polypeptide Slco1a1 in liver and kidney, 1a4 in liver, and Slc22a7 in kidney was decreased in db/db mice. In contrast, Abcc3 and 4 mRNA and protein expression was more than 2 fold higher in db/db male mouse livers as compared to C57BKS controls. Urine levels of APAP-glucuronide, -sulfate, and N-acetyl cysteine metabolites were higher in db/db mice.A severe diabetes phenotype/presentation significantly altered drug transporter expression in liver and kidney, which corresponded with urinary APAP metabolite levels.The prevalence of obesity and metabolic syndrome has increased at an alarming rate. By the year 2030, the number of adults with either type-1 or type-2 diabetes is estimated to be greater than 350 million [1]. Adult onset type-2 diabetes (T2DM) constitutes over 90% of all diabetes cases and is characterized by insulin resistance, abnormal insulin secretion, or both. Of these cases, it is estimated that 16% of people have undiagnosed or poorly managed diabetes (NIDDK National Health Interview survey, 2007–2009).It is well documented that Type-2 diabetes and hepatic steatosis are co-present [2]. The incidence of non-alcoholic fatty liver disease (NAFLD) is prevalent in 40 to 70% of patients with T2DM [3,4]. This type of liver disease originates as hepatic steatosis, and can progress to non-alcoholic steatohepatitis (NASH), cirrhosis, and end stage liver failure [5]. T2DM-related NAFLD is not fully understood, but it is known that leptin and insulin are important mediators in the progression of NAFLD [6]. Leptin is a hormone secreted by adipocyte