A protein of approximately 28,000 relative molecular mass (Mr) cross‐reacting with antiserum against the 28,000‐Mr rat renal calcium‐binding protein (calbindin‐D28k) has been localized in the kidney of a salientian amphibian, Rana catesbeiana. Cells reactive for calbindin‐D28k were found in the distal tubule at all stages of metamorphosis by the unlabeled antibody peroxidase‐antiperoxidase technique. Adult kidneys appeared to have more calbindin‐D28k‐positive cells. The renal corpuscle, neck, and proximal tubule were negative. An immunoreactive 28,000‐Mr band that comigrated with the band of calbindin‐D28k was visualized by the immunoblot technique. The finding of the 28,000‐Mr calbindin‐D in the anamniotic kidney demonstrates that this calcium‐binding protein (CaBP) is phylogenetically older than our previous studies of higher vertebrates had revealed (Rhoten et al., 1985). Although the function of calbindin‐D28k in the distal nephron is unknown, this CaBP can now be presumed to have functional significance in the mesonephric as well as the metanephric kidney.
All Science Journal Classification (ASJC) codes
- Agricultural and Biological Sciences (miscellaneous)