当前位置： SCI文献检索 > GENERAL AND COMPARATIVE ENDOCRINOLOGY期刊下所有文献 > Glucocorticoid receptor upregulation during seawater adaptation in a euryhaline teleost, the tilapia (Oreochromis mossambicus).

Glucocorticoid receptor upregulation during seawater adaptation in a euryhaline teleost, the tilapia (Oreochromis mossambicus).

Abstract：

:Cortisol is an important seawater (SW) osmoregulatory hormone in the Mozambique tilapia (Oreochromis mossambicus), a highly euryhaline cichlid able to live in environments ranging from fresh water (FW) to salinities well in excess of full-strength seawater. Previous studies indicate that cortisol may promote SW adaptation by increasing gill chloride cell differentiation, Na(+)/K(+)-ATPase activity and subsequent excretion of excess salt following seawater acclimation. Despite cortisol's widely accepted role as a SW-adapting hormone, cortisol receptor regulation during SW acclimation is not well understood. The purpose of these studies was to determine whether the intracellular glucocorticoid receptor (GR) might be regulated in a manner consistent with cortisol's actions in SW adaptation. Saturation radioligand binding assays were conducted on gill cytoplasm preparations from fish sampled 4 and 24h and 4 and 14 days after transfer from FW to 2/3 SW or FW (control). Affinity (K(d)) of the gill GR remained constant over the timecourse, while numbers of receptors (B(max)) in SW fish were significantly elevated compared with controls at 24h and 4 days after transfer. Plasma osmolality was higher in fish transferred to SW for 24h, 4 days, and 14 days compared with those animals moved to FW. Plasma cortisol levels and hepatic cortisol binding remained constant between SW and FW fish throughout the timecourse of the salinity challenge. These studies indicate that seawater acclimation is accompanied by a specific upregulation of intracellular GR numbers in gill tissue. The lack of increase in circulating cortisol following SW adaptation may reflect enhancement of clearance of the steroid. It appears that an increase in cortisol receptors, which is closely associated with the rise in blood osmotic pressure that accompanies SW exposure, is an important component of cortisol's ability to promote SW adaptation in the tilapia.

journal_name

Gen Comp Endocrinol

journal_title

General and comparative endocrinology

authors

Dean DB,Whitlow ZW,Borski RJ

doi

10.1016/s0016-6480(03)00053-4

keywords:

subject

Has Abstract

pub_date

2003-06-01 00:00:00

pages

112-8

issue

eissn

0016-6480

issn

1095-6840

pii

S0016648003000534

journal_volume

132

pub_type

杂志文章

在线工具

Glucocorticoid receptor upregulation during seawater adaptation in a euryhaline teleost, the tilapia (Oreochromis mossambicus).