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.
Department of Medicine, Sahlgrenska University Hospital, Göteborg University, SE-413 45 Göteborg, Sweden. Hans.Herlitz@medic.gu.se
H
H
Herlitz
L
L
Bokemark
E L
EL
Alenhag
J
J
Wikstrand
B
B
Fagerberg
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