EFFECTS OF RACE/ETHNICITY ON ADIPONECTIN LEVELS AND INSULIN ACTION

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Type 2 diabetes (T2DM) and its long-term complications are more prevalent in African Americans than in White Americans (1,2). The pathogenesis of the racial differences in glucose/insulin metabolism and insulin sensitivity remains uncertain. Despite the enormous progress and advancements in understanding the pathogenetic basis of impaired glucose tolerance (IGT) and T2DM, the mechanisms for beta cell dysfunction and insulin resistance that are pivotal for T2DM remain uncertain. There is increasing evidence to indicate that proinflammatory adipocytokines could mediate some of the metabolic derangements leading to T2DM and cardiovascular diseases (CVD) (3-28). Among them, Adiponectin has received greater attention. Adiponectin has been shown to predict future type 2 diabetes, hypertension and coronary artery disease (3-5, 10). The present project will explore the differential role of adiponectin in glucose homeostasis, insulin action and metabolism and substrate oxidation in healthy African Americans (AA) and White Americans (WA). The study will also identify whether the circulating trimers, heterotrimers, hexatrimers etc. are different in African Americans and White Americans. Healthy AA and WA will be recruited to participate in the study. Information collected will include related blood samples, anthropometric measurements, DEXA scan for body composition, abdominal CT to evaluate visceral adiposity, euglycemic-isotope clamp to assess insulin sensitivity and indirect calorimetry to assess resting energy expenditure. It is hopeful that this project will help show how ethnicity plays a role in glucose/insulin metabolism and insulin sensitivity and how adiponectin relates to theses factors. It is hopeful that the stimulation of endogenous adiponectin levels could provide a novel approach for the future prevention and management of type 2 diabetes and perhaps cardiovascular risk factors in African Americans.