Insulin binding to erythrocytes of nonpregnant women: a reevaluation, underlining the importance of body weights even in nonobese subjects.
Insulin binding to erythrocytes was measured in 18 healthy, non-obese women in the follicular phase and in 6 women in the mid-luteal phase of the same menstrual cycle. The presence of 55 nM and 220 nM monoclonal anti-IGF I receptor antibody (alpha-IR3) reduced only the number of low affinity binding sites for insulin by 20% and 33%, respectively. Women with relative body weights 110-119% had a lower number of high affinity receptors and an increased high affinity compared to women with relative body weights 91-109%. In women with relative body weights greater than or equal to 100%, maximum specific binding and high affinity constants increased and the receptor numbers decreased from the follicular to the luteal phase, whereas in women with relative body weights less than 100% the parameter changes were reverted. The data indicate: (1) erythrocytes contain two different classes of binding sites for insulin, (2) IGF I receptors might contribute to low-affinity binding of insulin to erythrocytes and (3) the relative body weight must be considered even for 'non-obese' control groups used in insulin binding studies of various clinical conditions.
Desoye
G
G
Department of Obstetrics and Gynecology, Karl-Franzens-University, Graz, Austria.
Schmon
B
B
Gmoser
G
G
Friedl
H
H
Urdl
W
W
Weiss
P A
PA
D000328:Adult; D001835:Body Weight; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D008597:Menstrual Cycle / Q000097:blood; D015233:Models, Statistical; D011972:Receptor, Insulin / Q000378:metabolism*
D007328:Insulin; D011972:Receptor, Insulin