Liquid chromatography tandem mass spectrometry for the quantification of steroid hormone profiles in blubber from stranded humpback whales (Megaptera novaeangliae).

Greta Dalle Luche,Fletcher M J Mingramm,Ashley S P Boggs,Susan Bengtson Nash,John R Kucklick,Kathleen Hunt

doi:10.1093/conphys/coz030

Abstract

Marine mammal blubber is known to have quantifiable concentrations of steroid hormones and is increasingly chosen as a matrix for the detection of these reproductive and stress biomarkers. Steroid hormones act through complex cascades, often in concert, yet studies conducted on cetaceans have rarely measured more than two steroids simultaneously. Due to the role of steroid hormones in multiple physiological processes, and variability in concentration among individuals, data on single compounds are often difficult to interpret. Here a liquid chromatography tandem mass spectrometry method for the simultaneous analyses of multiple steroid hormones in cetacean blubber was validated and applied to samples from 10 stranded humpback whales (Megaptera novaeangliae). Progesterone, 17α-hydroxyprogesterone, testosterone, androstenedione, oestrone, oestradiol, cortisone, cortisol, corticosterone and 11-deoxycorticosterone were reliably (relative standard deviation on six replicates <15%) and accurately (recovery of an amended sample between 70% and 120%) quantified, but not 11-deoxycortisol. With the exception of progesterone, testosterone, oestradiol and cortisol, these compounds were quantified for the first time in humpback whales. Given that blubber is frequently collected from free-swimming cetaceans in ongoing research programs, the technique developed here could substantially strengthen understanding and monitoring of the physiological condition of these species.

Highlights

Steroid hormones are frequently used as biomarkers of stress, sexual maturity and reproductive state in cetaceans
The limits of detection and quantification for 11-deoxycorticosterone were notably higher than those of the other steroids, no negative effect was observed on the repeatability and accuracy of this compound
We quantified two additional hormones, oestradiol and oestrone, to those measured in the first application of this technique in bottlenose dolphin blubber (Boggs et al, 2017)

Summary

Introduction

Steroid hormones are frequently used as biomarkers of stress, sexual maturity and reproductive state in cetaceans. After baseline hormone values have been established for each species and tissue type, steroids can be used for studying wild population dynamics and health parameters in cetaceans, including large whales (Rolland et al, 2012; Wasser et al, 2017; Pallin et al, 2018a; Trumble et al, 2018). The narrative surrounding steroid hormones in cetaceans is mainly dictated by consideration of one or rarely two or three hormones. This translates to a knowledge gap in our understanding of marine mammal endocrinology. Some physiological states involve downstream endocrinological signals (e.g. spermatogenesis or pregnancy) that entail changes in the concentrations of multiple steroid hormones. Information based upon multiple steroid hormones enhances the possibility of a more accurate physiological diagnosis

Methods

Results

Conclusion