The inter-relationship between insulin and chromium in hyperinsulinaemic euglycaemic clamps in healthy volunteers

Abstract

Evidence in the literature suggests that the trace element chromium may have a role in glucose homeostasis through the regulation of insulin action. We have previously reported a significant reduction in plasma chromium levels in healthy individuals, following a 75 g oral glucose load, and after meals and glucose-dependent uptake of chromium in insulin-dependent tissues in vitro. However, in vivo it is unclear whether the changes in plasma chromium relate to changes in plasma glucose or insulin. The present study describes a series of euglycaemic hyperinsulinaemic clamps designed to attempt to define the initiator of changes in plasma chromium levels in ten healthy individuals. The data showed a significant (P < 0.01) reduction in fasting plasma chromium levels following glucose infusion and an initial bolus of insulin. Significant (P < 0.02) increases in post-clamp urinary chromium excretion were insufficient to explain the decrease in plasma levels. During the recovery phase of an extended two-phase clamp protocol we found plasma insulin levels decreased by 70% within 10 min, associated with an increase in plasma chromium levels of 30% and no significant change in plasma glucose level. These data indicate that alterations in plasma glucose are unlikely to be directly related to changes in plasma chromium, whilst supporting the hypothesis that plasma insulin may influence plasma levels of this trace element. In contrast, plasma zinc was unaffected throughout these clamp studies.

The biomimetic [Cr3O(O2CCH2CH3)6(H2O)3]+ decreases plasma insulin, cholesterol, and triglycerides in healthy and type II diabetic rats but not type I diabetic rats

“…The biologically active form of chromium, chromodulin, is maintained in insulin-sensitive cells in its apo (metal-free) form. In response to insulin, chromium concentrations in the blood decrease as chromium is moved by transferrin to insulin-sensitive cells [21,46,47,48]. Chromodulin has a large chromic ion binding constant and becomes loaded with the metal ion.…”

Role of Chromium in Human Health and in Diabetes

“…Our literature search did not find any study that evaluated the effect of chromium supplementation on insulin sensitivity by using the gold standard for assessing insulin action, i.e., the hyperinsulinemic-euglycemic clamp. One study (65) used the euglycemic clamp, but only to assess the relationship of blood chromium and insulin and did not supplement the subjects. Another study (21) evaluated subjects with a hyperglycemic clamp and demonstrated that significant increases in glucose utilization were observed and associated with increases in ␤-cell sensitivity to glucose following chromium supplementation.…”

Pixe Technique: A Handy Tool for Investigation of Trace Elements in Some Anti Diabetic Medicinal Plants

“…are responsible for the secretion of insulin from β-cells of islets of langerhans 30 and also important for the glucose metabolic regulation 31,32 . Inorganic elements such as Cu, Zn, Cr, and Sr have been implicated in some metabolic disorders that include diabetes 33,34 .…”