Comparative Endocrinology

F.M. Anne McNabb, Department of Biology
Virginia Polytechnic Institute, Blacksburg, Virginia

What themes unify comparative endocrinology?

Two types of themes that receive considerable attention in comparative endocrinology are:

1. Evolutionary patterns - For example, ancestral organisms may have a single hormone that performs a series of functions while more recently evolved organisms may have several related hormones each of which performs a single one of these functions.

2. Chemical structure and function of hormones in different organisms - In some cases, hormones are identical chemically in all vertebrates (e.g. thyroid hormones) and may have similar functions (e.g. thyroid hormones trigger developmental events in all vertebrates). In other cases, the same hormone may have different effects in different organisms (e.g. thyroid hormones increase metabolism in birds and mammals but do not do so in other vertebrates). In yet other cases the chemical structure of a hormone may differ even in closely related species, a common situation for complex protein hormones.

How diverse is the field of comparative endocrinology?

The word "comparative" indicates that this field focuses on hormones in many different types of animals, both vertebrate and invertebrate. In contrast to general endocrinology, which emphasizes similarities, usually among mammals, comparative endocrinology has a much broader focus that includes field and environmental endocrine studies, evolutionary studies, and behavioral endocrinology in many different animal systems.

How did you and other colleagues become
interested in comparative endocrinology?

Many people become interested in endocrinology by trying to answer mechanistic questions about how physiological and biochemical events are controlled in organisms. The nervous and endocrine systems together provide integrated control of all physiological events in animals.

Why is your field exciting?

Endocrinology helps us to understand how control systems coordinate developmental and functional events in organisms so that these biological events can proceed in an orderly way.

How does the study of comparative endocrinology help society? Why should the public care?

Endocrinology provides the basic information on which much of pharmacology is based. As understanding of endocrine disorders improves, the potential for designing good treatment options also is improved. In many cases, specific animal models are very useful for studying particular problems or disorders in the laboratory, or in serving as sources of ideas for novel treatment possibilities. Thus, common laboratory rats aren't always the best models for all medically relevant research.

What is a typical day like?

Comparative endocrinologists may be either field or laboratory-oriented and this determines some aspects of how they spend their time. Hormone measurements, studies of the receptors that bind hormones in the tissues, and measurements of hormone effects are all examples of laboratory assessments commonly used by endocrinologists in their research. Comparative endocrinologists who are faculty members in universities also are involved in teaching and in guiding graduate students in learning about research.

What other jobs are there in comparative endocrinology besides those in academia or research labs?

Here are some examples:

  • drug development (biotechnology) jobs with pharmaceutical companies.
  • sales jobs with pharmaceutical companies.
  • jobs with companies that produce animal feed, to study hormone-nutrition interactions.
  • governmental jobs in agencies such as the Environmental Protection Agency or wildlife service, e.g. monitoring the effects of endocrine disrupting chemicals.