Characterization of Circulating Steroid Hormone Profiles in the Bottlenose Dolphin (Tursiops truncatus) by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Thomas M. Galligan, Lori Schwacke, Dorian S. Houser, Randall Wells, Teresa Rowles, Ashley Russell
Circulating steroid hormone concentrations are typically measured by immunoassays, which have imperfect specificity and are limited to the measurement of a single hormone per assay. Here we demonstrate that reverse phase solid phase extraction (SPE) coupled to liquid chromatography tandem mass spectrometry (LC-MS/MS) allows for the simultaneous, precise, and accurate measurement of at least six (and potentially eight) steroid hormones at endogenous concentrations in dolphin blood matrices - plasma and serum. These six steroid hormones include three hormones that have been measured previously in bottlenose dolphin blood (progesterone, testosterone, and cortisol) and three hormones which have never been quantified in dolphin blood (17-hydroxyprogesterone, androstenedione, and cortisone). While 17β-estradiol and estrone were not detected endogenously, we were able to accurately and precisely measure spiked quantities of each. Measures from plasma were more precise and thus we recommend plasma as the preferred matrix for this analytical method. In order to facilitate comparison of current and future plasma-based studies to previous serum-based studies, we characterize the relationships between hormone measurements in matched plasma and serum, and found that measurements across matrices are significantly and positively correlated. Lastly, to demonstrate potential applications of this method, we examine how steroid hormone profiles vary by pregnancy, sexual maturity, and stress status - pregnancy is associated with elevated progesterone, adult males have higher androgens, and capture stress seems to be associated with elevated corticosteroids. Overall, we conclude that this method will enable investigators to more thoroughly and efficiently evaluate steroid hormone homeostasis in bottlenose dolphins. These methods can potentially be applied to the assessment of sexual maturity/seasonality, pregnancy status, and stress in free-ranging bottlenose dolphins.
, Schwacke, L.
, Houser, D.
, Wells, R.
, Rowles, T.
and Russell, A.
Characterization of Circulating Steroid Hormone Profiles in the Bottlenose Dolphin (Tursiops truncatus) by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS), General and Comparative Endocrinology, [online], https://doi.org/10.1016/j.ygcen.2018.04.003, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=924260
(Accessed December 10, 2023)