Resistance to the antilipolytic effect of insulin in adipocytes of African-American compared to Caucasian postmenopausal women.
High fatty acid (FA) flux is associated with systemic insulin resistance, and African-American (AA) women tend to be more insulin resistant. We assessed possible depot and race difference in the antilipolytic effect of insulin in adipocytes isolated from abdominal (Abd) and gluteal (Glt) subcutaneous (sc) adipose tissue of overweight, postmenopausal AA and Caucasian (C) women. Percent body fat, fasting insulin, visceral adiposity, and adipocyte size was higher in AA women. Disinhibited lipolysis (presence of adenosine deaminase) per unit adipocyte surface area was similar in Abd and Glt and in AA and C. However, rates of 'basal' [submaximal phenylisopropyl adenosine (PIA)-suppressed] and insulin-suppressed lipolysis were higher in Abd of AA compared with C women even after adjustment for percent fat and visceral fat area. The race difference in rates of PIA- and insulin-suppressed lipolysis in AA were correlated with their hyperinsulinemia, but AA race, independent of fasting insulin, was associated with lower responsiveness (percent suppression) to submaximal insulin concentrations, although sensitivity (ED50) was not affected. Overall, these data are consistent with the hypothesis that decreased responsiveness of Abd adipocytes to antilipolytic effectors may contribute to higher FA availability and thereby to racial differences in insulin resistance.
Fried
Susan K
SK
Geriatric Research and Education Clinical Center, Baltimore Veterans Administration Medical Center, Baltimore, MD, USA. skfried@bu.edu
Tittelbach
Thomas
T
Blumenthal
Jacob
J
Sreenivasan
Urmila
U
Robey
Linda
L
Yi
Jamie
J
Khan
Sumbul
S
Hollender
Courtney
C
Ryan
Alice S
AS
Goldberg
Andrew P
AP
D050153:Abdominal Fat / Q000187:drug effects / Q000378:metabolism; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D000328:Adult; D001741:Black or African American; D000368:Aged; D002081:Buttocks; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005260:Female; D006801:Humans; D007328:Insulin / Q000378:metabolism* / Q000494:pharmacology; D007333:Insulin Resistance / Q000208:ethnology*; D007545:Isoproterenol / Q000494:pharmacology; D008066:Lipolysis / Q000187:drug effects; D008875:Middle Aged; D010660:Phenylisopropyladenosine / Q000494:pharmacology; D017698:Postmenopause / Q000378:metabolism*; D044465:White People
D005230:Fatty Acids, Nonesterified; D007328:Insulin; D010660:Phenylisopropyladenosine; D007545:Isoproterenol