Characteristics of Human Platelet Insulin Receptor

Human platelet insulin receptors were investigated in 21 young healthy Japanese subjects. Insulin specific binding was evident in the platelets, and binding sites had two constant orders of affinity. The high affinity site (Kaff=4.4×1010M-1) had a low capacity (55 sites/cells) while the lower affinity site (Kaff=2.9× 107M-1) had a higher capacity (1400/cells). Binding of 125I-insulin to platelets was maximal at 4°C, and at pH 7.4-8.0. These results indicate that human platelet insulin receptors have characteristics similar to those seen in lymphocyte insulin receptors.This evidence suggests that further investigation of the action of insulin on platelets is warranted.