Increase in the type 2 insulin-like growth factor receptors in the rat kidney during compensatory growth.

We have observed an increase in binding of IGF-I and IGF-II to microsomes obtained from rat kidneys undergoing compensatory growth following contralateral nephrectomy. This increase was evident by the 4th day and it preceded observable growth of the kidney. Binding returned to control levels just prior to the flattening of the growth curve of the kidney. The increase was due to an increase in the type 2 binding sites, the only type unequivocally present, from 95.3 +/- 2.7 to 117.2 +/- 4.1 pM/150 micrograms of microsome protein at its maximum at 4 days.