Dr. George E. Bentley Profile

Dr. George E. Bentley

Dr. Bentley's research includes avian reproductive biology, neuroendocrinology and behavior.


In particular, Dr. Bentley is interested in the mechanisms that allow the brain to regulate an animal's endocrine status to keep it in balance with its physical and social environment.

Though the hypothalamus is responsible for regulating hormones, what is less understood is how external cues are detected and used to signal hormonal changes.

How do temperature and light intensity, and auditory and visual cues cause hormonal changes in an individual? How does bird song cause rapid changes in circulating sex hormones?

These are some of the questions Dr. Bentley is looking to answer.

Evolutionary Perspective

Before hormones kick in to have a physiological influence, the brain has to monitor and then respond to an external stimulus. To influence reproductivity, the stimulus must affect the gonadotropin-releasing hormone (GnRH) system.

While most research on endocrine and behavior responses have focused on the end-result for the individual, Dr. Bentley has approached his research with evolution in mind:

"Of course, anthropomorphically speaking, the behavioral endpoint is all that matters as far as the individual involved is concerned: 'Do I get my mate', 'Did I scare off an intruder?', but how the brain (and the GnRH system) has adapted to effect these responses is rather more important from an evolutionary point of view."

Dr. Bentley: Q&A

Why a scientist?

Growing up in an agricultural environment helped fuel my interest in biology. We had the space to keep Muscovy ducks and I remember being fascinated by their physiology and behavior. It was fun to find nests and to be able to walk right up to the mother and pick her up as she incubated the eggs.

I didn’t know this at the time, but the mother’s incubation behavior and reticence to move from the nest was the result of the hormone prolactin acting upon her brain.

This early interest led me to study biology at university inEngland, but it was only when I was exposed to basic research as part of my undergraduate course that it dawned on me that this was what I wanted to do for the rest of my life.

Coincidentally enough, my first research project was on circadian, or daily, activity rhythms in mice; one of the people who co-discovered the part of the brain responsible for generating circadian rhythms is Dr. Irving Zucker, also in the IB department.

What led you to the questions you are now investigating in your research?

My early interests led me to study hormones as chemical mediators of changes in physiology and behavior. I soon realized that I was going to have to study the brain if I was going to find out any answers to how the environment influences changes in blood hormone concentrations. Equally interesting to me is how hormones then feed back to the brain and influence behavior. I feel extremely fortunate to have found my way to Berkeley where there is a strong history of endocrinology research.

How does your research affect your classroom and/or lab?

I always hope to be able to convey my excitement about biological processes in general.  It’s extremely gratifying to see students learn about endocrinology while at the same time pushing back the frontiers of knowledge by performing research themselves. I also enjoy it when students test my knowledge limits by asking probing questions.

For more information, visit:

Bentley Faculty Page

Helen Wills Neuroscience Institute

April 2006