Parathyroid hormone-related protein: a calcium regulatory factor in sea bream (Sparus aurata L.) larvae

Am J Physiol Regul Integr Comp Physiol. 2001 Sep;281(3):R855-60. doi: 10.1152/ajpregu.2001.281.3.R855.


The effects of an N-terminal peptide (amino acids 1-38) of Fugu parathyroid hormone-related protein (PTHrP 1-38) on calcium regulation of larval sea bream were investigated in seawater (36 per thousand) and after transfer to dilute seawater (12 per thousand). Exposure to PTHrP 1-38 evoked a 1.5-fold increase in calcium influx in both full-strength and dilute seawater. Calcium influx in dilute seawater-adapted larvae was roughly one-half that observed in full-strength seawater controls. PTHrP 1-38 also reduced drinking of fish in seawater but, at all concentrations tested, was without effect in dilute seawater. The amount of water imbibed was 55% lower in dilute seawater than in seawater. PTHrP 1-38 exposure affected the calcium influx route: the main contribution of calcium uptake shifted from intestinal absorption to extraintestinal uptake, probably by the induction of a dose-dependent increase in branchial (active) transport. Moreover, seawater-adapted fish exposed to 1 nM and 10 mM PTHrP 1-38 experienced a 2.5-fold reduction in overall calcium efflux. Overall, the calciotropic action of PTHrP 1-38 resulted in a dose-dependent increase in net calcium balance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological / drug effects
  • Adaptation, Physiological / physiology
  • Animals
  • Calcium / metabolism*
  • Calcium / pharmacokinetics
  • Dose-Response Relationship, Drug
  • Drinking / drug effects
  • Fresh Water
  • Ion Transport / drug effects
  • Larva
  • Parathyroid Hormone-Related Protein
  • Peptide Fragments / pharmacology
  • Proteins / metabolism*
  • Sea Bream
  • Seawater


  • Parathyroid Hormone-Related Protein
  • Peptide Fragments
  • Proteins
  • parathyroid hormone-related-protein (1-38)
  • Calcium