Hyaluronate and hyaluronidase in the developing chick embryo kidney.

Changes in hyaluronate concentration and hyaluronidase activity were measured at progressive stages of chick embryo kidney development. Hyaluronate accumulates in the immature metanephros containing undifferentiated mesenchyme and early stages of tubular epithelium formation. Differentiation of the epithelium to mature tubules and renal corpuscles occurs over a period when hyaluronate concentrations are decreasing. The initial decrease in hyaluronate is accompanied by an increase in hyaluronidase activity in the metanephros. A similar peak of hyaluronidase activity was found to occur during mesonephros development. Chondroitin sulfate levels remain almost constant throughout the course of metanephric differentiation.