Differential expression of PTHrP and its receptor in pituitary gland and gills in estradiol-treated gilthead sea bream (Sparus auratus, L.). | - CCMAR -

Journal Article

TitleDifferential expression of PTHrP and its receptor in pituitary gland and gills in estradiol-treated gilthead sea bream (Sparus auratus, L.).
Publication TypeJournal Article
AuthorsBevelander, GS, Guerreiro, PM, Spanings, T, Flik, G
Year of Publication2011
JournalGen Comp Endocrinol
Volume173
Issue1
Date Published2011 Aug 1
Pagination199-204
ISSN1095-6840
KeywordsAnimals, Estradiol, Gills, Hypercalcemia, Parathyroid Hormone-Related Protein, Pituitary Gland, Receptor, Parathyroid Hormone, Type 1, Reverse Transcriptase Polymerase Chain Reaction, Sea Bream
Abstract

In the gilthead sea bream (Sparus auratus) 17β-estradiol (E₂) plays an important role in the synthesis of vitellogenin. During vitellogenesis, vitellogenin as a nutritional precursor protein is loaded with calcium, which requires elevated plasma calcium levels. This is accomplished via E₂-dependent processes. Reports have shown that hypercalcemic effects of E₂ are possibly mediated by another hypercalcemic factor, viz. parathyroid hormone related protein (PTHrP). To further investigate the possibility of PTHrP as a mediator of E₂-induced hypercalcemia, we investigated the local expression levels of the pthrp mRNA and of the gene coding for the PTHrP receptor, PTH1R (pth1r) in two tissues involved in the calcium regulation (gills, pituitary gland) of the sea bream treated with E₂. Compared to control, treatment with E₂ resulted in: significantly increased total calcium and plasma PTHrP levels (P<0.01), a down-regulation of pthrp mRNA in the pituitary gland (P<0.01), and up-regulation of expression levels for both pthrp and pth1r in the branchial system (P<0.05). These findings provide direct evidence for a mediating role of PTHrP in E₂ induced hypercalcemia, and in addition support the idea for the presence of two independent systems, an endocrine pituitary PTHrP system and a peripheral paracrine branchial PTHrP system.

DOI10.1016/j.ygcen.2011.05.017
Sapientia

http://www.ncbi.nlm.nih.gov/pubmed/21658390?dopt=Abstract

Alternate JournalGen. Comp. Endocrinol.
PubMed ID21658390
CCMAR Authors