Minoxidil, a KATP channel opener, accelerates DNA synthesis following partial hepatectomy in rats

A large number of studies have reported the action of K-ATP channel openers in accelerating the proliferation of hepatocytes and many other cell types in vitro. Few studies, however, have examined the proliferative effect of K-ATP channel openers in vivo. The aim of this study was to determine whether the K-ATP channel opener minoxidil accelerates liver regeneration after partial hepatectomy (PH) in vivo. Male Wistar rats underwent a 70% partial hepatectomy (PH) after receiving a subcutaneous injection of minoxidil (0.01 mg/kg or 0.03 mg/kg). Some of the rats were intravenously treated with 5-hydroxydecanoic acid (5-HD, 10 mg/kg) just before the minoxidil injection. Seventy-two hours after PH, DNA synthesis was immunohistochemically assessed by bromodeoxyuridine (BrdU) incorporation into the nuclei. Minoxidil induced significant and dose-dependent increase in the BrdU labeling index after PH, and 5-HD reversed this minoxidil-induced change. Minoxidil did not significantly affect the changes in liver weight and liver function after PH. The hepatic levels of prealbumin decreased by about 60% after PH and minoxidil inhibited the decrease. In conclusion, the K-ATP channel opener minoxidil enhanced DNA synthesis after PH without affecting the liver function.