| Title: | Sex and seasonal differences in mRNA expression of estrogen receptor alpha (ESR1) in red-sided garter snakes (Thamnophis sirtalis parietalis) |
| Author(s): | Ashton SE; Vernasco BJ; Moore IT; Parker MR; |
| Address: | "Department of Biology, James Madison University, Harrisonburg, VA 22807, United States; Graduate Program in Neuroscience, School of Medicine, University of Maryland, Baltimore, MD 21201, United States. Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, United States. Department of Biology, James Madison University, Harrisonburg, VA 22807, United States. Electronic address: mrockwellparker@gmail.com" |
| DOI: | 10.1016/j.ygcen.2018.05.026 |
| ISSN/ISBN: | 1095-6840 (Electronic) 0016-6480 (Linking) |
| Abstract: | "Estrogens are important regulators of reproductive physiology including sexual signal expression and vitellogenesis. For the regulation to occur, the hormone must bind and activate receptors in target tissues, and expression of the receptors can vary by sex and/or season. By simultaneously comparing circulating hormone levels with receptor expression, a more complete understanding of hormone action can be gained. Our study species, the red-sided garter snake (Thamnophis sirtalis parietalis), provides an excellent opportunity to study the interaction between sex steroid hormones and receptor expression in addition to sexual dimorphism and seasonality. During the spring mating season, male garter snakes rely exclusively on the female's skin-based, estrogen-dependent sex pheromone to direct courtship. Males can be stimulated to produce this sexual attractiveness pheromone by treatment with estradiol (E(2)), which also induces male vitellogenesis. Estrogen receptors (ESRs) are required to transduce the effects of estrogens, thus we used quantitative RT-PCR to analyze expression of ESR alpha (ERalpha; gene ESR1) mRNA in the skin and liver of wild caught male and female garter snakes across simulated spring and fall conditions in the laboratory. While ESR1 was present in the skin of both sexes, there were no sex or seasonal differences in expression levels. Liver expression of ESR1, however, was sexually dimorphic, with females showing greatest expression in fall when circulating E(2) concentrations were lowest. There were no statistically significant correlations between E(2) and ESR1 expression. Our data suggest that the skin of both sexes is sensitive to estrogen signaling and thus the production of sex pheromone is dependent on bioavailable levels of E(2). Female expression of ESR1 in the liver may increase in the fall to prime energy storage mechanisms required for vitellogenesis the following year" |
| Keywords: | "Animals Colubridae Estrogen Receptor alpha/metabolism Female Gonadal Steroid Hormones/*metabolism Male RNA, Messenger/*metabolism Seasons *Gene expression *Hormone receptor *Reptile *Seasonality *Sex steroids *Vitellogenesis *qPCR;Neuroscience;" |
| Notes: | "MedlineAshton, Sydney E Vernasco, Ben J Moore, Ignacio T Parker, M Rockwell eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. 2018/05/29 Gen Comp Endocrinol. 2018 Oct 1; 267:59-65. doi: 10.1016/j.ygcen.2018.05.026. Epub 2018 May 25" |
