Erythrocyte sodium-lithium countertransport activity and total body insulin-mediated glucose disposal in normoalbuminuric normotensive type 1 (insulin-dependent) diabetic patients.
Insulin resistance in Type 1 (insulin-dependent) diabetes mellitus may be associated with raised erythrocyte sodium-lithium countertransport activity in patients with hypertension, or nephropathy, or both. However, in these circumstances it is difficult to separate the impact of hypertension, hyperlipidaemia and nephropathy on erythrocyte sodium-lithium countertransport from that of insulin resistance. We have therefore examined the relationship between insulin-mediated glucose disposal and erythrocyte sodium-lithium countertransport in 41 normotensive (mean blood pressure 120/74 mmHg), normoalbuminuric (mean albumin excretion 6.2 micrograms/min), normolipidaemic (mean serum cholesterol 4.3 mmol/l and mean serum triglycerides 1.0 mmol/l) Type 1 diabetic patients. Erythrocyte sodium-lithium countertransport was on average 0.31 mmol Li.h-1.l erythrocytes-1 (range 0.07-0.69). Nine patients had values above 0.40 mmol Li.h-1.l erythrocytes-1 (0.51 +/- 0.10 mmol Li.h-1.l erythrocytes-1). The patients with high erythrocyte sodium-lithium countertransport were matched for age, sex, BMI, HbA1 and duration of diabetes, with nine patients with normal erythrocyte sodium-lithium countertransport. Insulin-mediated glucose disposal was evaluated during the last hour of a euglycaemic clamp (insulin 0.015 U.kg-1.h-1; blood glucose clamped at 7.0 mmol/l). The free insulin levels were comparable between the patients with high and normal erythrocyte sodium-lithium countertransport (37.2 +/- 14.7 mU/l and 34.7 +/- 17.2 mU/l respectively). Insulin-mediated glucose disposal was on average 3.1 +/- 1.5 (range 0.8-6.8) mg.kg-1.min-1.(ABSTRACT TRUNCATED AT 250 WORDS)
Catalano
C
C
Department of Medicine, University of Newcastle upon Tyne, UK.
Winocour
P H
PH
Thomas
T H
TH
Walker
M
M
Sum
C F
CF
Wilkinson
R
R
Alberti
K G
KG
D000328:Adult; D000419:Albuminuria; D017920:Antiporters; D001794:Blood Pressure; D002352:Carrier Proteins / Q000097:blood*; D002784:Cholesterol / Q000097:blood; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D005947:Glucose / Q000378:metabolism*; D015309:Glucose Clamp Technique; D006801:Humans; D007328:Insulin / Q000627:therapeutic use*; D007700:Kinetics; D008297:Male; D012016:Reference Values; D014280:Triglycerides / Q000097:blood
D017920:Antiporters; D002352:Carrier Proteins; D007328:Insulin; D014280:Triglycerides; C045885:sodium-lithium countertransporter; D002784:Cholesterol; D005947:Glucose