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

作者：Bevelander Gideon S; Guerreiro Pedro M; Spanings Tom; Flik Gert^*

来源：General and Comparative Endocrinology, 2011, 173(1): 199-204.

DOI：10.1016/j.ygcen.2011.05.017

• Estradiol
• PTHrP
• PTH1R
• Pituitary gland
• Gill
• Sea bream

In the gilthead sea bream (Sparus auratus) 17 beta-estradiol (E(2)) 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 E(2)-dependent processes. Reports have shown that hypercalcemic effects of E(2) are possibly mediated by another hypercalcemic factor, viz. parathyroid hormone related protein (PTHrP). To further investigate the possibility of PTHrP as a mediator of E(2)-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 E(2). Compared to control, treatment with E(2) 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 prh1r in the branchial system (P < 0.05). These findings provide direct evidence for a mediating role of PTHrP in E(2) 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.

• 出版日期2011-8-1