Improvement of insulin resistance, blood pressure and interstitial pH in early developmental stage of insulin resistance in OLETF rats by intake of propolis extracts

Biochem Biophys Res Commun. 2013 Mar 22;432(4):650-3. doi: 10.1016/j.bbrc.2013.02.029. Epub 2013 Feb 14.

Abstract

Propolis, a resinous mixture collected from plants by the Apis mellifera bee, contains high level nutrient factors including vitamins, polyphenols, and amino acids that would be expected to improve insulin sensitivity. Insulin resistance would secondarily cause elevation of blood pressure and increase the risk of cardiovascular diseases. The purpose of this study is to investigate the effect of propolis extracts on blood glucose levels and blood pressures in an early developmental stage of insulin resistance in Otsuka Long-Evans Tokushima Fatty (OLETF) rats. OLETF rats (10 weeks old) were divided into three different groups: normal diet, 0.1% propolis diet, and 0.5% propolis diet. After 8 weeks, blood glucose levels, blood pressures, plasma metabolic factors and hormones, and interstitial fluid pH were measured. Casual blood glucose levels were decreased associated with a reduction of plasma insulin levels in both propolis diet groups compared with normal diet group. Propolis decreased systolic blood pressure with no significant changes in plasma aldosterone levels. We also found that interstitial fluid pH in ascites, liver, and skeletal muscle was higher in rats fed propolis diet than rats fed normal diet. These data suggests that dietary propolis improves insulin sensitivity and blood pressures in the early stage of the process in development of insulin resistance, which may be mediated by suppression of metabolic acidosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / drug effects
  • Aldosterone / blood
  • Animals
  • Blood Glucose / drug effects
  • Blood Pressure / drug effects*
  • Body Weight / drug effects
  • Dietary Supplements*
  • Extracellular Fluid / chemistry
  • Extracellular Fluid / drug effects*
  • Hydrogen-Ion Concentration / drug effects
  • Insulin / blood
  • Insulin Resistance*
  • Propolis / administration & dosage*
  • Rats
  • Rats, Inbred OLETF
  • Urine / chemistry

Substances

  • Blood Glucose
  • Insulin
  • Aldosterone
  • Propolis