Effect of L-thyroxine on renal excretion of water and electrolytes in both normal and mercury-intoxicated rats.

The urine output and the change in excretion of electrolytes (sodium, potassium, calcium, chloride, inorganic phosphate) in rats following mercury-induced acute tubular lesions showed marked recovery during L-thyroxine therapy. The kidney mechanisms responsible for this effect are discussed, considering especially the observation that rats treated with L-thyroxine have a reduced urinary output, unlike other species, including man, which react with polyuria. The oliguric effect of thyroid hormone in rats is attributed to the greater length of the vasa recta and loops of Henle.