AJP - Renal Physiology, Vol 245, Issue 4 506-F511, Copyright © 1983 by American Physiological Society
Effects of calcitonin on the renal concentrating mechanism
C. de Rouffignac and J. M. Elalouf
The effects of salmon calcitonin on the renal concentrating mechanism were
investigated in homozygous DI Brattleboro rats. The levels of peptide
hormones believed to produce the same physiological responses as
antidiuretic hormone on the thick ascending limb (glucagon, parathyroid
hormone, and calcitonin) and the cortical collecting ducts (calcitonin)
were reduced by acute thyroparathyroidectomy and somatostatin
administration. In these hormone-deprived animals, the corticomedullary
concentration gradient was almost abolished; the (F/P)osmol at the tip of
the juxtamedullary nephrons was 1.19 +/- 0.05. Calcitonin administration
restored the gradient [(F/P)osmol = 1.85 +/- 0.14] and simultaneously
absolute and fractional water excretion fell significantly despite the
concomitant rise in the glomerular filtration rate. It is concluded that 1)
in the hormone-deprived animal, calcitonin administration consistently
enhances the corticomedullary concentration gradient, and 2) the effects of
hormone deprivation and calcitonin administration on the urinary
concentrating mechanism are compatible with direct stimulation by
calcitonin of electrolyte reabsorption along the thick ascending limb
and/or of the water permeability of the cortical collecting ducts.
