Calcitonin stimulates h+ secretion in rat kidney intercalated
cells.
Esteban, Siga, Pascal,houillier, B[acute]eatrice, Mandon, Gervaise
Moine, and Christian De Rouffignac.
CEA Saclay: Service de Biologie Cellulaire, Centre d'Etudes de
Saclay, Commissariat [grave]a l'Energie Atomique,91191 Gif-sur-Yvette
cedex, D[acute]epartement de Physiologie, Universit[acute]e Pierre et
Marie Curie, Institut National de la Sant[acute]e et de la Recherche
M[acute]edicale. Unit[acute]e 356, H[circumflex]opital Broussais,
75014 Paris, France
APStracts 3:0158F, 1996.
Calcitonin (CT) modulates rat intercalated cell (IC) functions of the
rat cortical collecting duct (CCD) (Am.?J. Physiol.?264: F221-F227,
1993). To characterize the specific function regulated by CT, rat
CCDs were perfused in vitro. Total CO2 net fluxes (JtCO2,
pmol/mm/min) and transepithelial voltage (Vt) were measured. Bath CT?
induced a significant tCO2 reabsorption . This effect was higher on
CCDs harvested from acid-loaded than from control rats. When HCO3-
secretion was blocked, CT also raised JtCO2 and Vt. When H+ secretion
was blocked, CT was ineffective on JtCO2 and Vt. When HCO3- secretion
was increased and H+ secretion inhibited, CT did not change JtCO2
whereas isoproterenol (ISO) increased tCO2 secretion from -13.5?+/
-?2.0 (control) to -?19.0?+/-?2.4 (ISO). In rat CCD studied under
these same preceding conditions, plus luminal amiloride to block the
Na+-depending Vt, CT did not alter Vt whereas ISO increased it by
4.5?+/-?0.7?mV. We conclude from these data that, in the rat CCD,
calcitonin stimulates H+ secretion, likely by so-called [alpha]IC
cells, whereas isoproterenol stimulates HCO3- secretion, likely
by?so-called [beta]-IC cells.
Received 6 March 1996; accepted in final form 2 September 1996.
APS Manuscript Number F77-6.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996