The National Institute of Diabetes & Digestive & Kidney Diseases

Obesity, diabetes and heart disease are characterized by resistance to insulin as a glucoregulatory hormone. African Americans, particularly African American women suffer disproportionately from these three conditions. We believe that sex differences in sensitivity to insulin’s ability to suppress lipolysis contribute to the accelerated development of obesity, diabetes and heart disease in African American women. The hypothesis of this research is that African American men are resistant to insulin as a glucoregulatory hormone and resistant to insulin as a fat regulatory hormone. In contrast, African American women are resistant to insulin as a glucoregulatory hormone but sensitive to insulin as a fat regulatory hormone. The frequently sampled intravenous glucose tolerance test is used to measure insulin’s action as a glucoregulatory hormone. Unfortunately there is no index of insulin’s action as a fat regulatory hormone. Hence we are working on the development of this index by obtaining free fatty acids during the frequently sampled glucose tolerance test. Our goal is be able to do one test to obtain information about both actions of insulin. However, the development of an index of free fatty acid sensitivity to insulin during the frequently sampled intravenous glucose tolerance test involves sophisticated mathematical modeling and will need to be validated. Therefore we have undertaken studies of whole body lipolysis and developed a collaboration with the Laboratory of Biological Modeling in NIDDK.

Tulloch-Reid MK, Hanson RL, Sebring NG, Reynolds JC, Premkumar A, Genovese DJ, Sumner AE Both subcutaneous and visceral adipose tissue correlate highly with insulin resistance in african americans. Obes Res (12): 1352-9, 2004. [Full Text/Abstract]

Sumner AE, Bergman RN, Vega GL, Genovese DJ, Cochran CS, Pacak K, Watanabe RM, Boston RC The multiphasic profile of free fatty acids during the intravenous glucose tolerance test is unresponsive to exogenous insulin. Metabolism (53): 1202-7, 2004. [Full Text/Abstract]

Boston RC, Stefanovski D, Moate PJ, Sumner AE, Watanabe RM, Bergman RN MINMOD Millennium: a computer program to calculate glucose effectiveness and insulin sensitivity from the frequently sampled intravenous glucose tolerance test. Diabetes Technol Ther (5): 1003-15, 2003. [Full Text/Abstract]

Boston RC, Sumner AE STATA: a statistical analysis system for examining biomedical data. Adv Exp Med Biol (537): 353-69, 2003. [Full Text/Abstract]

Sumner AE, Farmer NM, Tulloch-Reid MK, Sebring NG, Yanovski JA, Reynolds JC, Boston RC, Premkumar A Sex differences in visceral adipose tissue volume among African Americans. Am J Clin Nutr (76): 975-9, 2002. [Full Text/Abstract]

Tulenko TN, Sumner AE The physiology of lipoproteins. J Nucl Cardiol (9): 638-49, 2002. [Full Text/Abstract]

Sumner AE, Farmer NM, Cochran CS, Sebring NG, Vanevski K, Reynolds JC, Premkumar A, Boston RC Obese premenopausal African-American women with normal and impaired glucose tolerance have a similar degree of insulin resistance but differ in beta-cell function. Diabetes Care (24): 1978-83, 2001. [Full Text/Abstract]

Sumner AE, Falkner B, Diffenderfer MR, Barrett PH, Marsh JB A study of the metabolism of apolipoprotein B100 in relation to insulin resistance in African American males. Proc Soc Exp Biol Med (221): 352-60, 1999. [Full Text/Abstract]

Sumner AE, Kushner H, Sherif KD, Tulenko TN, Falkner B, Marsh JB Sex differences in African-Americans regarding sensitivity to insulin''s glucoregulatory and antilipolytic actions. Diabetes Care (22): 71-7, 1999. [Full Text/Abstract]

Sumner AE, Falkner B, Kushner H, Considine RV Relationship of leptin concentration to gender, menopause, age, diabetes, and fat mass in African Americans. Obes Res (6): 128-33, 1998. [Full Text/Abstract]

Sumner AE, Kushner H, Tulenko TN, Falkner B, Marsh JB The relationship in African-Americans of sex differences in insulin-mediated suppression of nonesterified fatty acids to sex differences in fasting triglyceride levels. Metabolism (46): 400-5, 1997. [Full Text/Abstract]