University of St Andrews
Sea Mammal Research Unit
SMRU > Research > Endocrinology


The endocrine system is the body’s signalling system that, through the production of proteins known as hormones, provides important homeostatic control and feedback information to the brain on the current status of a very wide range of physiological systems.  Because of the exquisite adaptation of marine mammals to their environment, the endocrine system has often also specifically adapted to function somewhat differently to the way it does in their terrestrial relatives.


Whilst some hormones have evolved and adapted in marine mammals, others are almost identical in structure to those found in most other vertebrate species, including man.  This means that hormone levels in the blood can be measured using the reagents and methods developed for laboratory species and humans.  Circulating hormone levels can then be related to different physiological states such as reproduction, fasting, moulting, growth and osmoregulation (water balance).  Where the structure of the hormones in marine mammals is very different this approach is not possible, more detailed molecular approaches have to be employed.


Ailsa Hall has investigated what hormones are important in respiratory control and diving physiology and how the structure of these varies among marine mammal species.  She is also working on how stress hormones are affected in seals and what hormonal controls are critical to osmoregulation in marine mammals. In addition she is working with Patrick Miller investigating reproductive and stress hormones in whale blow.

Ian Boyd has studied the relationship between heart rate and metabolic rate in seals and some seabirds, especially penguins mainly in collaboration with Pat Butler at the University of Birmingham and Jon Green at Liverpool University.

Paddy Pomeroy has studied how reproductive hormones signal important change in seals, such as the onset of oestrus and has currently has students studying behavioural endocrinology in grey seals.

Weaned grey seal pups experience physiological and endocrinological changes



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