Insulin resistance and not hyperinsulinaemia determines erythrocyte Na+/Li+ countertransport in non-insulin-dependent diabetes mellitus.
Insulin resistance and increased erythrocyte Na+/Li+ countertransport activity are well documented in subjects with essential hypertension, raising the question whether compensatory hyperinsulinaemia might be responsible for activating Na+/Li+ countertransport. We measured Na+/Li+ countertransport in 63 non-nephropathic non-insulin-dependent diabetic subjects (36 hypertensive, 27 normotensive), finding no correlation with fasting levels of insulin (r = 0.074, P = 0.28), despite using a sensitive and specific insulin assay. In contrast, in 33 of the subjects in whom insulin sensitivity was measured, Na+/Li+ countertransport correlated significantly with the whole body glucose clearance rate (r = -0.37, P = 0.036). It is concluded that increased Na+/Li+ countertransport may be a cellular marker for insulin resistance, but that hyperinsulinaemia is not likely to be the factor which mediates this relation.
Pinkney
J H
JH
University College London School of Medicine, Department of Medicine, Whittington Hospital, UK.
Denver
A E
AE
Foyle
W J
WJ
Foster
C
C
Yudkin
J S
JS
D000368:Aged; D017920:Antiporters / Q000032:analysis*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D004797:Enzyme-Linked Immunosorbent Assay; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D006801:Humans; D006946:Hyperinsulinism / Q000378:metabolism; D006973:Hypertension / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D007333:Insulin Resistance; D017136:Ion Transport; D008094:Lithium / Q000097:blood; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000097:blood
D017920:Antiporters; C045885:sodium-lithium countertransporter; D008094:Lithium; D011188:Potassium