AJP - Renal Physiology, Vol 257, Issue 6 1003-F1014, Copyright © 1989 by American Physiological Society

ARTICLES

Effects of glucagon on H(+)-HCO3- transport in Henle's loop, distal tubule, and collecting ducts in the rat

O. Mercier, M. Bichara, M. Delahousse, A. Prigent, F. Leviel and M. Paillard
Laboratoire de Physiologie et Physiopathologie Renale et Electrolytique, Universite Paris VII, Hopital Louis Mourier, Colombes, France.

Paired micropuncture experiments were carried out in somatostatin-infused volume-expanded rats to examine the effects of a glucagon infusion (0.05 ng.min-1.g body wt-1) on urinary acidification and tubular handling of bicarbonate. Whole kidney and single-nephron glomerular filtration rate were not affected by glucagon. In thyroparathyroidectomized (TPTX) rats, glucagon inhibited the reabsorption of total CO2 in Henle's loop. In intact animals, however, the latter effect was not observed. In the distal tubule accessible to micropuncture, net total CO2 absorption was observed during volume expansion plus somatostatin infusion, which reversed to net total CO2 secretion during glucagon infusion in Wistar rats; thus the late distal delivery of total CO2 increased almost 80%. Marked inhibition of urinary acidification occurred in all animals as evidenced by a rise in urine pH and bicarbonate excretion. Conversely, a somatostatin infusion, which decreased the plasma glucagon concentration, stimulated net total CO2 absorption along the distal tubule and augmented final urine acidification in Wistar rats. Finally, urine-minus-blood PCO2 during alkaline diuresis was significantly reduced by glucagon infusion in bicarbonate-loaded TPTX rats. We conclude that 1) glucagon inhibits bicarbonate absorption in superficial Henle's loop in TPTX but not in intact rats, and 2) glucagon stimulates bicarbonate secretion and/or inhibits proton secretion in the distal tubule and collecting ducts, which leads to reduced urinary acidification.

This article has been cited by other articles:

				Y. Yano, K. R. Cesar, M. Araujo, A. C. Rodrigues Jr., L. C. Andrade, and A. J. Magaldi Aquaporin 2 expression increased by glucagon in normal rat inner medullary collecting ducts Am J Physiol Renal Physiol, January 1, 2009; 296(1): F54 - F59. [Abstract] [Full Text] [PDF]

				P. Bansal and Q. Wang Insulin as a physiological modulator of glucagon secretion Am J Physiol Endocrinol Metab, October 1, 2008; 295(4): E751 - E761. [Abstract] [Full Text] [PDF]

				C. Helies-Toussaint, L. Aarab, J.-M. Gasc, J.-M. Verbavatz, and D. Chabardes Cellular localization of type 5 and type 6 ACs in collecting duct and regulation of cAMP synthesis Am J Physiol Renal Physiol, July 1, 2000; 279(1): F185 - F194. [Abstract] [Full Text] [PDF]

				R. F. Reilly and D. H. Ellison Mammalian Distal Tubule: Physiology, Pathophysiology, and Molecular Anatomy Physiol Rev, January 1, 2000; 80(1): 277 - 313. [Abstract] [Full Text] [PDF]

				D. Chabardes, D. Firsov, L. Aarab, A. Clabecq, A.-C. Bellanger, S. Siaume-Perez, and J.-M. Elalouf Localization of mRNAs Encoding Ca2+-inhibitable Adenylyl Cyclases along the Renal Tubule. FUNCTIONAL CONSEQUENCES FOR REGULATION OF THE cAMP CONTENT J. Biol. Chem., August 9, 1996; 271(32): 19264 - 19271. [Abstract] [Full Text] [PDF]