Zinc Supplementation Improves Glucose Homeostasis in High Fat-Fed Mice by Enhancing Pancreatic β-Cell Function

Nutrients. 2017 Oct 20;9(10):1150. doi: 10.3390/nu9101150.

Abstract

Zinc is an essential component of the insulin granule and it possibly modulates insulin secretion and signaling. Since insulin resistance is a hallmark in the development of type 2 diabetes mellitus, this study aimed at investigating if zinc supplementation is able to improve glucose tolerance and β-cell function in a model of insulin resistance. Male C57BL/6 mice were distributed in four groups according to the diet: normal fat (NF); normal fat supplemented with ZnCl₂ (NFZ); high-fat (HF); and, high-fat chow supplemented with ZnCl₂ (HFZ). Intraperitoneal glucose (ipGTT) and insulin (ipITT) tolerance, glycemia, insulinemia, HOMA-IR, and HOMA-β were determined after 15 weeks in each diet. Glucose-stimulated insulin secretion (GSIS) was investigated in isolated islets. The insulin effect on glucose uptake, metabolism, and signaling was investigated in soleus muscle. ZnCl₂ did not affect body mass or insulin sensitivity as assessed by ipITT, HOMA-IR, muscle glucose metabolism, and Akt and GSK3-β phosphorylation. However, glucose tolerance, HOMA-β, and GSIS were significantly improved by ZnCl₂ supplementation. Therefore, ZnCl₂ supplementation improves glucose homeostasis in high fat-fed mice by a mechanism that enhances β-cell function, rather than whole-body or muscle insulin sensitivity.

Keywords: diabetes mellitus; insulin; insulin resistance; zinc.

MeSH terms

  • Animals
  • Blood Glucose / metabolism*
  • Chlorides / administration & dosage
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / drug therapy
  • Diet, High-Fat*
  • Disease Models, Animal
  • Glycated Hemoglobin A / metabolism
  • Glycogen Synthase Kinase 3 / genetics
  • Glycogen Synthase Kinase 3 / metabolism
  • Homeostasis / drug effects*
  • Insulin / blood
  • Insulin / metabolism
  • Insulin Resistance
  • Insulin Secretion
  • Insulin-Secreting Cells / cytology
  • Insulin-Secreting Cells / drug effects*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / metabolism
  • Zinc / administration & dosage*
  • Zinc / blood
  • Zinc Compounds / administration & dosage

Substances

  • Blood Glucose
  • Chlorides
  • Glycated Hemoglobin A
  • Insulin
  • Zinc Compounds
  • zinc chloride
  • Glycogen Synthase Kinase 3
  • Zinc