Renin-angiotensin system and osmoregulation in the terrestrial chelonian Testudo hermanni Gmelin.

1. Renal renin activity, Na and K plasma urinary levels were studied in Testudo hermanni after salted diet, saline solution administration and furosemide injection. 2. Salt loading depressed renal renin activity whereas injection of the diuretic resulted in sodium loss and enhanced renal renin activity. 3. Results lead one to conclude the presence of a renin-angiotensin system with a direct action upon osmoregulation in these terrestrial chelonians.