Fuentes, J.Guerreiro, P. M.Modesto, TeresaRotllant, J.Canario, Adelino V. M.Power, Deborah2014-05-142014-05-142007Fuentes, J.; Guerreiro, P. M.; Modesto, T.; Rotllant, J.; Canario, A. V. M.; Power, D. M.A PTH/PTHrP receptor antagonist blocks the hypercalcemic response to estradiol-17 beta, American Journal of Physiology-Regulatory Integrative and Comparative Physiology, 293, 2, 956-960, 2007.0363-6119AUT: TMO00411; ACA00258; DPO00386;http://hdl.handle.net/10400.1/3936Estradiol (E2) increases circulating calcium and phosphate levels in fish, thus acting as a hypercalcemic and hyperphosphatemic factor during periods of high calcium requirements, such as during vitellogenesis. Since parathyroid hormone (PTH)-related protein (PTHrP) has been shown to be calciotropic in fish, we hypothesized that the two hormones could be mediating the same process. Sea bream (Sparus auratus) juveniles receiving a single intraperitoneal injection of piscine PTHrP(1-34) showed an elevation in calcium plasma levels within 24 h. In contrast, injections of the PTH/PTHrP receptor antagonist PTHrP(7-34) decreased circulating levels of calcium in the same period. Intraperitoneal implants of estradiol-17 (E2; 10 g/g) evoked significant increases of circulating plasma levels of calcium and phosphorus and a sustained increases of circulating plasma levels of PTHrP. However, a combined treatment of E2 and PTHrP(7-34) evoked a markedly lower calcium response compared with E2 alone. We conclude that PTHrP or a related peptide that binds the PTH/PTHrP receptor mediates, at least in part, the hypercalcemic effect of E2 in calcium and phosphate balance in fish.engCalciumPhosphateFishjournal article2014-05-08http://dx.doi.org/10.1152/ajpregu.00111.2007