Thyroid hormone, cortisol and leptin activity in Steller sea lions (Eumetopias jubatus) in response to thyroid stimulating hormone administered in different seasons

Abstract

The roles that the hormones reviewed here play in maintaining homeostasis are significant and must operate in a complimentary fashion to achieve balance. Complex reproductive physiology, challenging environment, and strong seasonal components of the SSL life history underscores the value of understanding how leptin, thyroid hormones and cortisol interact under optimal conditions in healthy animals. This will allow for the construction of seasonal benchmarks of animal condition. Because researchers are often limited to a single sample from a free-ranging individual, it is likely that a suite of hormones as a bioindicator of physiological status will provide a more in-depth profile of that individual. This information, in turn, can provide accurate information for the population at large.