Parathyroid hormone-related protein: a calcium regulatory factor in sea bream (Sparus aurata L.) larvae.
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.
Guerreiro
P M
PM
Centre of Marine Sciences, University of Algarve, Campus de Gambelas, 8000-810 Faro, Portugal.
Fuentes
J
J
Power
D M
DM
Ingleton
P M
PM
Flik
G
G
Canario
A V
AV
D000222:Adaptation, Physiological / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D004326:Drinking / Q000187:drug effects; D005618:Fresh Water; D017136:Ion Transport / Q000187:drug effects; D007814:Larva; D044162:Parathyroid Hormone-Related Protein; D010446:Peptide Fragments / Q000494:pharmacology; D011506:Proteins / Q000378:metabolism*; D021541:Sea Bream; D012623:Seawater
D044162:Parathyroid Hormone-Related Protein; D010446:Peptide Fragments; D011506:Proteins; C434741:parathyroid hormone-related-protein (1-38); D002118:Calcium