Effects of GH, prolactin and cortisol on hepatic heat shock protein 70 expression in a marine teleost Sparus sarba

Abstract

Heat shock protein 70 (HSP70) expression was assessed in hepatic tissue of a marine teleost Sparus sarba after exogenous hormone administration. Using a PCR-amplified, homologous HSP70 cDNA clone, as a probe in Northern analysis, we detected a 2·3 kb transcript which was elevated after exposure to a temperature 7 C above the ambient. For our studies on hormonal effects on HSP70 expression, groups of fish were administered recombinant bream GH (rbGH), ovine prolactin (oPRL) or cortisol daily over a 7-day period. Quantification of hepatic HSP70 transcript revealed that the administration of GH and PRL significantly reduced HSP70 mRNA abundance by 42% and 54% from saline-injected fish respectively. Also hepatic HSP70 levels were reduced by 76% and 64% as determined by immunoblotting after rbGH and oPRL treatment respectively. The administration of exogenous cortisol did not alter hepatic HSP70 mRNA or protein levels in S. sarba. The results obtained in this study are the first evidence for hormonal modulation of heat shock protein expression in fish. The significance of these results is discussed within the context of current knowledge on the roles of these hormones in teleostean stress response.

Development of a black sea bream fibroblast cell line and its potential use as an in vitro model for stress protein studies

“…The cell line is relatively easy to maintain as we have deduced the optimum FBS requirement and growth temperature. Over the past few years we have been studying the effects of hormones on hsp70 expression in vivo (Deane et al 1999(Deane et al , 2000 but due to endocrine axis overlap and crosstalk, firm conclusions about hormone specific effects on hsp70 expression await the application of suitable in vitro models. The development of the cell line in the present study may prove to be useful towards these studies.…”

Growth hormone transgenesis and polyploidy increase metabolic rate, alter the cardiorespiratory response and influence HSP expression to acute hypoxia in Atlantic salmon (Salmo salar) yolk-sac alevins

“…The cellular stress response to low environmental O 2 levels is variable in fish, and high levels of tissue, cell and temporal specificity in terms of the levels of HSP expression have been reported (Airaksinen and Nikinmaa, 1995;Currie and Tufts, 1997;Currie and Boutilier, 2001;Currie et al, 2010). Furthermore, a decrease in HSP70 mRNA production in hepatic tissue of sparids (family Sparidae) has been reported after exogenous administration of growth hormone (Deane et al, 1999). Despite this body of research, we know very little regarding the effects of ploidy and/or transgenesis on the cellular stress response in fish.…”

Growth hormone attenuates branchial HSP70 expression in silver sea bream

“…The earliest study to imply possible involvement of GH and PRL on fish HSP expression was performed using exogenous administration of recombinant bream GH or ovine prolactin to silver sea bream (Deane et al 1999). In this study it was found that both hormones reduced hepatic HSP70 mRNA and protein amounts in comparison with saline-treated controls.…”

“…However, much less is known about the effect of hormones on the regulation and expression of HSPs and most studies that have investigated hormone effects on fish HSP expression have used cortisol. For example silver sea bream (Sparus sarba), that were administered intraperitoneal injections of cortisol did not have any changes in hepatic HSP70 levels (Deane et al 1999). Subsequently, studies on rainbow trout (Oncorhynchus mykiss) and tilapia (Oreochromis mossambicus) also demonstrated that elevated cortisol per se did not alter basal HSP70 levels in hepatic or gill tissues (Basu et al 2001(Basu et al , 2002b.…”