This Article Full Text Full Text (PDF) Submit a related Letter to the Editor Purchase Article View Shopping Cart Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tataranni, P. A. Articles by Ravussin, E. Search for Related Content PubMed PubMed Citation Articles by Tataranni, P. A. Articles by Ravussin, E.

Pima Indian Males Have Lower ß-Adrenergic Sensitivity Than Caucasian Males

Clinical Diabetes and Nutrition Section, National Institute of Diabetes Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona 85016

Address all correspondence to: E. Ravussin, Ph.D., NIH, 4212 N. 16th Street, Phoenix, Arizona 85016. E-mail: Eric_Ravussin{at}nih.gov

Abstract

The sympathetic nervous system controls cardiovascular homeostasis and regulates energy metabolism. Pima Indians, a population with a low prevalence of hypertension and a high prevalence of obesity, have low sympathetic nervous activity, compared with Caucasians. Preliminary findings suggest that they may also have a low ß-adrenergic sensitivity. We studied ß-adrenergic sensitivity in 87 nondiabetic normotensive individuals [52 Pima Indians (35 males/17 females) and 35 Caucasians (24 males/11 females)], matched for age and body weight. Chronotropic sensitivity to ß-adrenergic stimulation was assessed by the dose of isoproterenol necessary to increase heart rate by 25 beats per minute [chronotropic dose-25 (CD25)]. Despite a similar basal heart rate and arterial blood pressure, Pimas tended to have lower ß-adrenergic sensitivity than Caucasians (CD25 = 2.37 ± 2.27 vs. 1.57 ± 1.38 µg, P = 0.07; mean ± SD). This difference was significant in males (CD25 = 3.03 ± 2.39 vs. 1.85 ± 1.56 µg, P = 0.02) but not in females (CD25 = 1.01 ± 1.17 vs. 0.96 ± 0.61 µg, P = 0.99). In males only, CD25 was positively correlated to percent body fat (r = 0.36, P < 0.01). After adjustment for percent body fat, ß-adrenergic sensitivity was still significantly lower in Pima than in Caucasian males (CD25 = 3.44 ± 2.24 vs. 2.57 ± 1.60 µg, P = 0.05). In conclusion, our data suggest that increased adiposity is accompanied by decreased ß-adrenergic sensitivity in males only. However, at each level of adiposity, Pima Indian males have lower ß-adrenergic sensitivity than Caucasian males. In combination with a low sympathetic nervous system activity, a reduced ß-adrenergic sensitivity may contribute to the low prevalence of hypertension and the high prevalence of obesity observed in Pima Indians.

This article has been cited by other articles:

				F. L. Bellino NIA Supports Minority Investigators and Research that Addresses Health Disparities Between Minority and Non-Minority Elderly Populations Sci. Aging Knowl. Environ., February 13, 2002; 2002(6): vp1 - 1. [Full Text]

				C. Weyer, R. E. Pratley, S. Snitker, M. Spraul, E. Ravussin, and P. A. Tataranni Ethnic Differences in Insulinemia and Sympathetic Tone as Links Between Obesity and Blood Pressure Hypertension, October 1, 2000; 36(4): 531 - 537. [Abstract] [Full Text] [PDF]

				A. Balasubramanyam, S. McKay, P. Nadkarni, A. S. Rajan, A. Garza, V. Pavlik, J. A. Herd, F. Jahoor, and P. J. Reeds Ethnicity affects the postprandial regulation of glycogenolysis Am J Physiol Endocrinol Metab, November 1, 1999; 277(5): E905 - E914. [Abstract] [Full Text] [PDF]