|
|
||||||||
COMPARATIVE AND EVOLUTIONARY PHYSIOLOGY
Centro de Ciências do Mar, CIMAR Laboratório Associado, Universidade do Algarve, Campus de Gambelas, Faro, Portugal
Submitted 20 December 2005 ; accepted in final form 1 June 2006
Parathyroid hormone-related protein (PTHrP) is a factor associated with normal development and physiology of the nervous, cardiovascular, immune, reproductive, and musculoskeletal systems in higher vertebrates. It also stimulates whole body calcium uptake in sea bream (Sparus auratus) larvae with an estimated 60% coming from intestinal uptake in seawater. The present study investigated the role of PTHrP in the intestinal calcium transport in the sea bream in vitro. Unidirectional mucosal-to-serosal and serosal-to-mucosal 45Ca fluxes were measured in vitro in duodenum, hindgut, and rectum mounted in Ussing chambers. In symmetric conditions with the same saline, bathing apical and basolateral sides of the preparation addition of piscine PTHrP 134 (6 nM) to the serosal surface resulted in an increase in mucosal to serosal calcium fluxes in duodenum and hindgut and a reduction in serosal to mucosal in the rectum, indicating that different mechanisms are responsive to PTHrP along the intestine. In control asymmetric conditions, with serosal normal and mucosal bathed with a saline similar in composition to the intestinal fluid, there was a net increase in calcium uptake in all regions. The addition of 6 nM PTHrP 134 increased net calcium uptake two- to threefold in all regions. The stimulatory effect of PTHrP on net intestinal calcium absorption is consistent with a hypercalcemic role for the hormone. The results support the view that PTHrP, alone or in conjunction with recently identified PTH-like peptides, counteracts in vivo the hypocalcemic effects of stanniocalcin.
fish; intestine; hypercalcemia
This article has been cited by other articles:
![]() |
J. Fuentes, C. Haond, P. M. Guerreiro, N. Silva, D. M. Power, and A. V. M. Canario Regulation of calcium balance in the sturgeon Acipenser naccarii: a role for PTHrP Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2007; 293(2): R884 - R893. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Fuentes, P. M. Guerreiro, T. Modesto, J. Rotllant, A. V. M. Canario, and D. M. Power A PTH/PTHrP receptor antagonist blocks the hypercalcemic response to estradiol-17beta Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2007; 293(2): R956 - R960. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. M. Guerreiro, J. L. Renfro, D. M. Power, and A. V. M. Canario The parathyroid hormone family of peptides: structure, tissue distribution, regulation, and potential functional roles in calcium and phosphate balance in fish Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2007; 292(2): R679 - R696. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |