Immunoreactive Tamm-Horsfall protein in the kidney and skin of the frog Rana temporaria.

Tamm-Horsfall protein (THP) is the main protein in normal human urine, and is found in the thick limb of the Loop of Henle in human kidney, and in other mammalian species. The skin of the frog. Rana temporaria, has similar physiological properties to this mammalian kidney tissue. In the present study, an immunohistological method involving an antibody to human THP was used to investigate the distribution of this distinctive protein in frog kidney and skin, and to compare its distribution with that found in the kidney tubules of rat and rabbit. THP-positive material was detected in the distal renal tubules and nephric duct of frogs, and was also located in the superficial epidermis of skin. It is suggested that its presence in amphibian skin is consistent with the hypothesis that THP is an important component of tissues that absorb sodium and chloride ions, but remain impermeable to water.