Two components of the neuroendocrine-hormonal response to long-term treatment of acarbose, adipose tissue-derived leptin and central neuropeptide Y (NPY), were investigated in the ICR mice on a high-carbohydrate diet. Acarbose, administered 5 or 50 mg per 100 g diet for four weeks, dose dependently suppressed body weight gain. The body weight gain was reduced along with the amount of daily food intake in 50 mg acarbose-treated group at 7th and 28th day 5 or 50 mg acarbose treatment administered for four weeks reduced leptin mRNA levels to 62% and 77% of the control group, demonstrating that the amount of leptin mRNA in adipocytes correlates with body weight. As dose of acarbose increased, leptin mRNA level also increased, suggesting that potent inhibition of alpha-glycosidase by a higher dose of acarbose furthers the enzyme activity and leptin gene consequently. On the other hand, central expression level of NPY gene was increased significantly compared with the control group at the same amount of acarbose administered, reflecting that leptin and NPY operate in a negative-feedback circuit to regulate body fat stores.
Acarbose* ; Adipocytes ; Adipose Tissue ; Animals ; Body Weight ; Diet* ; Eating ; Hand ; Leptin ; Mice* ; Mice, Inbred ICR ; Neuropeptide Y* ; Neuropeptides* ; RNA, Messenger

Mitochondrial ATP-sensitive potassium (mitoKATP) channels play a role in early and late ischemic preconditioning. Nevertheless, the subunit composition of mitoKATP channels remains unclear. In this study, we investigated the subunit composition of mitoKATP channels in mitochondria isolated from rat cardiac myocytes. Mitochondria were visualized using the red fluorescence probe, Mitrotracker Red, while mitoKATP channels were visualized using the green fluorescence probe, glibenclamide-BODIPY. The immunofluorescence confocal microscopy revealed the presence of Kir6.1, Kir6.2 and SUR2 present in the cardiac mitochondria. Western blot analysis was carried to further investigate the nature of mitoKATP channels. For SUR proteins, a 140-kDa immunoreactive band that corresponded to SUR2, but no SUR1 was detected. For Kir6.2, three bands (~4, ~6, and ~0 kDa) were detected, and a specific ~6-kDa immunoreactive band corresponding to Kir6.1 was also observed. These observations suggest that the subunits of mitoKATP channels in rat myocytes include Kir6.1, Kir6.2, and a SUR2-related sulfonylurea-binding protein.
Animals ; Blotting, Western ; Fluorescence ; Fluorescent Antibody Technique ; Ischemic Preconditioning ; KATP Channels* ; Microscopy, Confocal ; Mitochondria ; Muscle Cells ; Myocytes, Cardiac* ; Potassium ; Rats*