AJP - Regulatory, Integrative and Comparative Physiology, Vol 250, Issue 6 980-R983, Copyright © 1986 by American Physiological Society
Effect of intracerebroventricular calcitonin on renal hydromineral excretion in sheep
B. H. Appelgren, S. Arver and G. B. Sagulin
The localization of calcitonin in hypothalamic tissue and cerebrospinal
fluid and calcitonin binding sites in circumventricular organs suggests
involvement in neural mechanisms, possibly hydromineral balance. Therefore,
we compared the effects of intracerebroventricular and intravenous
infusions of porcine calcitonin (0.04-0.05 mU X kg-1 X min-1) on renal
water, Ca, Mg, Na, and K excretions. The intracerebroventricular
administration of calcitonin for 60 min induced a pronounced increase (P
less than 0.01) in free water clearance, from a preinfusion value of -0.73
+/- 0.45 to +3.02 +/- 1.15 ml/min at the end of the infusion. In contrast,
the free water clearance was unaltered during the intravenous infusion of
calcitonin. Renal Ca excretion fell significantly (53%) 40 min after the
end of the intracerebroventricular infusion of calcitonin, whereas the
corresponding intravenous infusion of calcitonin did not change (P greater
than 0.05) urinary Ca excretion. Renal Mg excretion was increased (P less
than 0.01) during the intracerebroventricular infusion of calcitonin but
was not altered during intravenous infusion of calcitonin. Urinary
excretions of Na and K were not affected by either intracerebroventricular
or intravenous administration of calcitonin. It is concluded that
calcitonin can act centrally to modify renal water, Ca, and Mg excretions.
