Chromium chloride increases insulin‐stimulated glucose uptake in the perfused rat hindlimb

[[abstract]]Aim To determine the effect of chromium chloride (CrCl3) on healthy skeletal muscle glucose uptake in the absence and presence of submaximal insulin using the rat hindlimb perfusion technique. Methods Sprague–Dawley rats were randomly assigned to an experimental group: basal (Bas), chromium chloride (Cr), submaximal insulin (sIns) or chromium chloride plus submaximal insulin (Cr‐sIns). Results Insulin significantly increased [H3]‐2 deoxyglucose (2‐DG) uptake in the gastrocnemius muscles. Additionally, Cr‐sIns displayed greater rates of 2‐DG uptake than sIns (Cr‐sIns 6.86 ± 0.74 μmol g h−1 vs. sIns 4.83 ± 0.42 μmol g h−1). There was no difference between Cr and Bas treatment groups. It has been speculated that chromium works to increase glucose uptake by increasing insulin signalling. We found that Akt and AS160 phosphorylation was increased in the sINS treatment group, while chromium treatment had no additional effect on Akt or AS160 phosphorylation in the absence or presence of insulin. Cr‐sIns significantly increased plasma membrane GLUT4 concentration above that of sIns (Cr‐sIns 72.22 ± 12.7%, sIns 53.4 ± 6.1%), but in the absence of insulin, chromium had no effect. Conclusion Exposure of healthy skeletal muscle to chromium may increase skeletal muscle insulin‐stimulated GLUT4 translocation and glucose uptake. However, these effects do not appear to result from enhanced insulin signalling proximal to AS160

Assays for insulin and insulin-like metabolic activity based on hepatocytes, myocytes and diaphragms.

Despite the eminent importance of studies with primary and cultured adipocytes or adipose tissues on the basis of their physiological role in the regulation of lipid and carbohydrate metabolism in humans in combination with the relative low expenditure in preparing adipocytes of high quality and number, compounds and drug candidates for future antidiabetic and antiobesity therapy have to be analyzed for their effects in primary and cultured hepatocytes and myocytes or liver and muscle tissues, too. In principle, the majority of the assays described above for adipocytes can be adapted for the use with hepatocytes and myocytes. However, the following selection takes into account the relative contribution of each process monitored to its role in the whole-body regulation of intermediary metabolism in the normal and disease state. Moreover, technical aspects, such as requirement for a special equipment and applicability in throughput screening assays for drug discovery, were additional criteria