Increased insulin receptors in carbohydrate-sensitive subjects: a mechanism for hyperlipaemia in these subjects?
Twenty male subjects, 11 normal and 9 carbohydrate-sensitive, participated in a study in which the effect of feeding diets low in copper (1.03 mg/d) on the number and affinity of insulin receptors was determined. Since carbohydrate-sensitive subjects are hyperinsulinaemic, it was anticipated that they would demonstrate a down-regulation of insulin receptors. The subjects were fed a low copper diet for 11 weeks and then replenished with copper (3 mg/d) for 3 weeks. Regardless of diets fed, carbohydrate-sensitive subjects showed increased insulin binding. The increase was due to the number of receptors without any change in their affinity. This unusual and unexpected observation in carbohydrate-sensitive subjects suggests an altered response of the insulin receptor, namely the failure of plasma insulin to down-regulate the number of receptors. It is possible that such an alteration could lead to a shift of the biological response curve of insulin to the left in some target tissues thereby causing hyperlipaemia by diverting glucose into triglyceride. The exact mechanism of hyperlipaemia in carbohydrate-sensitive subjects remains to be clarified.
D000328:Adult; D000704:Analysis of Variance; D001786:Blood Glucose / Q000378:metabolism; D050260:Carbohydrate Metabolism; D003300:Copper / Q000008:administration & dosage* / Q000097:blood; D004032:Diet; D005934:Glucagon / Q000097:blood; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood; D008055:Lipids / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011972:Receptor, Insulin / Q000378:metabolism*; D014280:Triglycerides / Q000097:blood
D001786:Blood Glucose; D007328:Insulin; D008055:Lipids; D014280:Triglycerides; D003300:Copper; D005934:Glucagon; D011972:Receptor, Insulin