QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Campbell, W. W. Articles by Birge, Z. K. Search for Related Content PubMed PubMed Citation Articles by Campbell, W. W. Articles by Birge, Z. K.

---

Human Nutrition and Metabolism

Pinitol Supplementation Does Not Affect Insulin-Mediated Glucose Metabolism and Muscle Insulin Receptor Content and Phosphorylation in Older Humans^1,2

Wayne W. Campbell³, Mark D. Haub^*, James D. Fluckey, Richard E. Ostlund, Jr^**, John P. Thyfault, Hannah Morse-Carrithers, Matthew W. Hulver and Zonda K. Birge

Department of Foods and Nutrition, Purdue University, West Lafayette, IN; ^* Department of Human Nutrition, Kansas State University, Manhattan, KS; Nutrition, Metabolism, and Exercise Laboratory, Donald W. Reynolds Department of Geriatrics, Little Rock, AR, and the Geriatric Research, Education, and Clinical Center, Central Arkansas Veterans Healthcare System, Little Rock, AR; ^** Department of Medicine, Washington University, St. Louis, MO; and Departments of Physiology and Biochemistry, Brody School of Medicine, East Carolina University, Greenville, NC

³To whom correspondence should be addressed. E-mail: campbellw{at}purdue.edu.

This study assessed the effect of oral pinitol supplementation on oral and intravenous glucose tolerances and on skeletal muscle insulin receptor content and phosphorylation in older people. Fifteen people (6 men, 9 women; age 66 ± 8 y; BMI 27.9 ± 3.3 kg/m²; hemoglobin A1c 5.39 ± 0.46%, mean ± SD) completed a 7-wk protocol. Subjects were randomly assigned to groups that during wk 2–7 consumed twice daily either a non-nutritive beverage (Placebo group, n = 8) or the same beverage with 1000 mg pinitol dissolved into it (Pinitol group, n = 7, total dose = 2000 mg pinitol/d). Testing was done at wk 1 and wk 7. In the Pinitol group with supplementation, 24-h urinary pinitol excretion increased 17-fold. The fasting concentrations of glucose, insulin, and C-peptide, and the 180-min area under the curve for these compounds, in response to oral (75 g) and intravenous (300 mg/kg) glucose tolerance challenges, were unchanged from wk 1 to wk 7 and were not influenced by pinitol. Also, pinitol did not affect indices of hepatic and whole-body insulin sensitivity from the oral glucose tolerance test and indices of insulin sensitivity, acute insulin response to glucose, and glucose effectiveness from the intravenous glucose tolerance test, estimated using minimal modeling. Pinitol did not differentially affect total insulin receptor content and insulin receptor phosphotyrosine 1158 and insulin receptor phosphotyrosine 1162/1163 activation in vastus lateralis samples taken during an oral-glucose–induced hyperglycemic and hyperinsulinemic state. These data suggest that pinitol supplementation does not influence whole-body insulin-mediated glucose metabolism and muscle insulin receptor content and phosphorylation in nondiabetic, older people.

KEY WORDS: • D-chiro-inositol • C-peptide • oral glucose tolerance test • intravenous glucose tolerance test

This article has been cited by other articles:

				G. Sethi, K. S. Ahn, B. Sung, and B. B. Aggarwal Pinitol targets nuclear factor-{kappa}B activation pathway leading to inhibition of gene products associated with proliferation, apoptosis, invasion, and angiogenesis Mol. Cancer Ther., June 1, 2008; 7(6): 1604 - 1614. [Abstract] [Full Text] [PDF]