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Q&A with Dr. Ned Place

Dolphin hormone Q&A with Dr. Ned Place

Dr. Place is an associate professor at Cornell’s College of Veterinary Medicine and director of the endocrinology laboratory in the Animal Health Diagnostic Center.

How did the AHDC get involved in this study?

Cornell’s Diagnostic Endocrinology Laboratory had collaborated with NOAA on dolphin hormone tests in the past, so it was a natural partnership to continue when Dr. Lori Schwacke contacted us in 2011 about doing more testing. We didn’t know which samples were from sick or healthy dolphins, if the dolphins were captured in the area that was affected by the spill (Barataria Bay, LA) or in an unaffected area (Sarasota Bay, FL).  That information wasn’t available to us until Dr Schwacke called us after we’d sent the results.

What kind of tests did you perform?

Using the blood (serum) samples we received, we did a battery of hormone tests, including cortisol, aldosterone, and thyroid function tests.

What evidence links the abnormal hormonal conditions you found to oil exposure?

Prior studies have established connections between petroleum oil exposure and abnormalities in hormone secretion from the adrenal gland in marine mammals. Other investigators focused on mink as a model for effects of oil spills on sea otters, and they found evidence of adrenal insufficiency, an outcome that appears to be similar to our results in the dolphins.

How could the oil have interfered with hormones?

Cortisol is produced and secreted by the adrenal gland, but the process begins in a region of the brain called the hypothalamus. It sends a hormonal signal to the neighboring pituitary gland, which then releases another hormone into the blood, which then travels to the adrenal cortex and stimulates the production of cortisol. Inhaled or ingested oil could interfere with any step in that process.

What struck you most about the study’s results?

One of the saddest things I encountered when working on this study was seeing animals with such low health scores and poor prognoses for survival.

What was it like to collaborate with such a large diverse team?

I came away really impressed with the NOAA scientists. Their scientific and epidemiological acumen is top-notch and particularly well suited to the work they do. Seeing and hearing how they handle dolphins was fascinating.

What more would you like to know?

I study reproductive biology in my research at Cornell, so I’d be interested in understanding more about why these dolphins’ reproductive output has been compromised.