Relation of kidney tissue somatomedin-C/insulin-like growth factor I to postnephrectomy renal growth in the rat.

In kidney tissue extracts, we observed elevated somatomedin-C (SmC) tissue concentrations in the kidney remaining after nephrectomy compared to those in the kidney removed at surgery or kidneys from sham-operated animals. In hypophysectomized animals, we observed a response of the same magnitude, but from significantly lowered basal SmC concentrations. In neither case did nephrectomy affect SmC levels in serum or other tissues studied (liver and lung). The increased tissue levels of SmC in the regenerating kidney, with a return to baseline levels within 30 days, along with the absence of elevated serum levels suggest a local role for this mitogen in organ growth.