Sodium/lithium countertransport, insulin resistance, insulin peptides and microalbuminuria in clinically healthy 58-year-old men.
The activity of the erythrocyte transport system, sodium/lithium countertransport (SLC), has been linked to the metabolic syndrome characterized by insulin resistance and compensatory hyperinsulinaemia. We measured SLC and insulin sensitivity with the euglycaemic hyperinsulinaemic clamp method in a patient sample (n = 93) randomly selected from a large clinically healthy group of 58-year-old men (n = 818). The lipid profile, blood pressure, body mass index (BMI) and insulin were also analysed. There was a significant difference (P < 0.001) in SLC between subjects with the metabolic syndrome (n = 19) and subjects without any components of this syndrome (n = 20). There was a highly significant correlation between SLC and BMI, waist/hip ratio, total body fat mass, serum triglycerides, plasma insulin, proinsulin split products and C-peptide in a univariate analysis. There was also a significant correlation between SLC and insulin sensitivity measured as insulin-mediated glucose uptake (P < 0.01). In multiple regression analysis, only two of the variables showing univariate significance were independently correlated to SLC, i.e. serum triglycerides (P < 0.001) and BMI (P < 0.01). The subjects with a SLC value in the highest tertile had a 6-fold higher prevalence of insulin resistance (low-insulin-mediated glucose uptake) as compared with those with a SLC value in the lowest tertile. We conclude that, in clinically healthy 58-year-old men from the general population, erythrocyte SLC is closely linked to metabolic syndrome, in particular to obesity, triglycerides and insulin resistance.
Herlitz
H
H
Department of Medicine, Sahlgrenska University Hospital, Göteborg University, SE-413 45 Göteborg, Sweden. Hans.Herlitz@medic.gu.se
Bokemark
L
L
Alenhag
E L
EL
Wikstrand
J
J
Fagerberg
B
B
D000419:Albuminuria / Q000097:blood*; D017920:Antiporters / Q000097:blood*; D015992:Body Mass Index; D004912:Erythrocytes / Q000378:metabolism; D015309:Glucose Clamp Technique; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008094:Lithium / Q000097:blood; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood; D012964:Sodium / Q000097:blood; D013577:Syndrome; D014280:Triglycerides / Q000097:blood
D017920:Antiporters; D014280:Triglycerides; C045885:sodium-lithium countertransporter; D008094:Lithium; D012964:Sodium