Effects of selected minerals on leptin secretion in streptozotocin-inducedhyperglycemic mice

The effects of lithium, magnesium, vanadate, and zinc on leptinemia and lep tin secretion by adipose tissue were investigated in streptozotocin-(STZ) i nduced hyperglycemic mice. After the administration of studied minerals in drinking water for 4 weeks, fasting serum leptin concentrations were elevat ed, accompanied by normoglycemia in STZ-injected mice, regardless which min eral was provided (P < 0.05). However, the in vitro administration of lithi um, magnesium, and vanadate did not significantly influence the leptin secr etion of adipose tissue. A low zinc treatment (0.1 mM) augmented, whereas b oth a pharmacological treatment of zinc (1 mM) and zinc depletion (1 mM TPE N) attenuated, leptin secretion (P < 0.05). The present study shows that ST Z-induced hyperglycemic mice have hypoleptinemia and reduced leptin secreti on by adipose tissue. Moreover, these defects can be improved by a moderate zinc administration.