Abstract:

Blubber, a specialized form of adipose tissue in marine mammals, has been identified as a useful matrix for the assessment of steroid hormone homeostasis in cetaceans. However, blubber cortisol measurements are not quantitatively predictive of circulating cortisol concentrations in bottlenose dolphins. In other mammals, adipose tissue metabolizes steroid hormones. Thus, we propose that the disagreement between blubber and blood cortisol in bottlenose dolphins could be due in part to metabolism of corticosteroids in blubber. The purpose of this study is to characterize the ability of blubber to interconvert cortisol and cortisone using an in vitro design. Blubber microsomes were collected by differential centrifugation and were treated with cortisol or cortisone and appropriate cofactor. Conversion of cortisol to cortisone (and vice versa) was measured by liquid-chromatography tandem mass spectrometry. This dataset contains measured values of cortisol and cortisone from these experiments.

Suggested Citation:

Galligan, Thomas. 2018. Evidence for stress steroid metabolism by marine mammal blubber. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N74B2ZSR

Publications:

Galligan, T. M., Schwacke, L. H., McFee, W. E., & Boggs, A. S. P. (2018). Evidence for cortisol–cortisone metabolism by marine mammal blubber. Marine Biology, 165(7). doi:10.1007/s00227-018-3373-4

Purpose:

To characterize the ability of dolphin blubber to interconvert cortisol and cortisone using an in vitro design.

Data Parameters and Units:

Sample ID, Cortisone (ng), Cortisol (ng)

Methods:

Microsomes were isolated from dolphin blubber. A solution of cortisol (experiment 1) or cortisone (experiment 2) in methanol was added to reaction tubes. The concentration of cortisol or cortisone was 1 micromolar. Methanol was dried. Microsomes, buffer, and cofactor were then added to microsomes. The cofactors applied were Nicotinamide adenine dinucleotide phosphate (NADP plus) and Nicotinamide adenine dinucleotide phosphate-H (NADPH) for experiment 1 (cortisol) and experiment 2 (cortisone), respectively, at a concentration of 2 millimolar. Microsomes were exposed for 90 minutes and then concentration of cortisone (experiment 1) or cortisol (experiment 2) were measured by liquid-chromatography tandem mass spectrometry. Sample IDs used in file are unique sample IDs assigned by lab and have no meaning.

Individual Files: