The adult fruit bat (Rousettus aegyptiacus) expresses only calbindin-D9K (vitamin D-dependent calcium-binding protein) in its kidney

1. 1. Immunohistochemical examination of sections of adult bat (Rousettus aegyptiacus) kidney failed to show the expression of calbindin-D28K in any tubules. 2. 2. Calbindin-D9K was found to occur in the distal convoluted tubules. 3. 3. Purification of the putative calbindin-D9K protein revealed its migration in non-denaturing polyacrylamide gel electrophoresis (PAGE) to be Ca-sensitive. 4. 4. On 17% SDS-PAGE gels the protein had an apparent M r of less than 12,000. 5. 5. The absence of calbindin-D28K from the kidney is unusual, but until roles are assigned to calbindins the significance of this finding will remain unclear.