Renal expression and functions of aquaporin 1 and aquaporin 4 in cattle.

ABSTRACT

Aquaporin (AQP) 1 and AQP 4 are members of the aquaporin water channel family that play an important role in reabsorption of water from the renal tubular fluid to concentrate urine. Studies of renal AQPs have been performed in human, rodents, sheep, dogs and horses. We studied nephron segment-specific expression of AQP 1 and AQP 4 using immunohistochemical staining on paraffin sections of bovine kidneys. AQP 1 was moderately expressed in endothelium of the cortical capillary network, vasa recta, and glomerular capillaries. AQP 4 was moderately expressed only in cytoplasm of epithelial cells in proximal tubules. We concluded that AQP 1 and AQP 4 in the bovine kidney showed some differences from other species in renal trans-epithelial water transport.