The Effect of 17α-Ethynilestradiol and GPER1 Activation on Body and Muscle Growth, Muscle Composition and Growth-Related Gene Expression of Gilthead Seabream, Sparus aurata L.

Maria D Ayala,Alfonsa García-Ayala,Francisco Gil,Daniel Garcia De La Serrana,María P García Hernández,Elena Chaves-Pozo,Victoria Gómez,Isabel Cabas,Marta Arizcun

doi:10.3390/ijms222313118

Abstract

Endocrine-disrupting chemicals include natural and synthetic estrogens, such as 17α-ethynilestradiol (EE2), which can affect reproduction, growth and immunity. Estrogen signalling is mediated by nuclear or membrane estrogen receptors, such as the new G-protein-coupled estrogen receptor 1 (GPER1). The present work studies the effect of EE2 and G1 (an agonist of GPER1) on body and muscle parameters and growth-related genes of 54 two-year-old seabreams. The fish were fed a diet containing EE2 (EE2 group) and G1 (G1 group) for 45 days and then a diet without EE2 or G1 for 122 days. An untreated control group was also studied. At 45 days, the shortest body length was observed in the G1 group, while 79 and 122 days after the cessation of treatments, the shortest body growth was observed in the EE2 group. Hypertrophy of white fibers was higher in the EE2 and G1 groups than it was in the control group, whereas the opposite was the case with respect to hyperplasia. Textural hardness showed a negative correlation with the size of white fibers. At the end of the experiment, all fish analyzed in the EE2 group showed a predominance of the gonadal ovarian area. In addition, the highest expression of the mafbx gene (upregulated in catabolic signals) and mstn2 (myogenesis negative regulator) was found in EE2-exposed fish.

Highlights

Endocrine-disrupting chemicals (EDCs) encompass both naturally produced compounds, such as estrogens and androgens, and a wide range of industrial chemicals released from many sources into the environment
The first G-protein-coupled estrogen receptor 1 (GPER1)-selective ligand identified was G1 [17,18], which has been extensively used to explore the biological significance of GPER1 in different tissues and organs [19]
In relation to the condition factor (CF), this was significantly lower in the EE2 group than in the G1 group, whereas the C group did not show significant differences compared to other groups

Summary

Introduction

Endocrine-disrupting chemicals (EDCs) encompass both naturally produced compounds, such as estrogens and androgens, and a wide range of industrial chemicals released from many sources into the environment. These compounds are capable of altering the function of the endocrine system and modulate reproduction, immunity and growth, among other things [1,2,3,4]. The disruptive effects of this compound vary according to dose, time of exposure, age and the stage in the reproductive cycle of the treated individuals [5,6,7,8,9,10,11,12,13,14,15,16]. The first GPER1-selective ligand identified was G1 [17,18], which has been extensively used to explore the biological significance of GPER1 in different tissues and organs [19]

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Conclusion