Anxious zoo officials trying to determine whether giant panda is pregnant

Panda keepers gather urine for hormone tests to determine if Mei Xiang is pregnant, driving samples in a cooler to their laboratory in Front Royal, Va.
By Michael E. Ruane
Washington Post Staff Writer
Wednesday, April 28, 2010

The frozen liquid is in two vials that have been placed in a paper cup beside two freezer packs in a battered Styrofoam box on which is written in black marker: "Return to Panda House."

The specimen, which has been sucked off the floor of the National Zoo's Giant Panda compound with a plastic syringe, has just arrived by car at the Smithsonian Conservation Biology Institute in Front Royal, Va. There, lab technician Sarah Putman pulls on her rubber gloves and prepares to analyze it.

The precious liquid is panda urine. And at the moment it contains vital clues to the future of Washington's giant panda population, currently holding at two.

Anxious zoo officials are trying this week to determine whether their female giant panda, Mei Xiang, is pregnant. She was artificially inseminated in January, and zoo scientists think she is at the end of her pregnancy cycle.

Experts say that means there will be, probably within days, either a new panda cub or an announcement that Mei Xiang has experienced a false or pseudo-pregnancy, which she has had the past three years.

The cycle is tracked, in part, by monitoring the level of the panda's progesterone, which rises at the start and falls steeply at the end. The cycle is considered over when the hormone level drops back to "baseline" and stays there without fluctuating for several days.

The hormone is found in the panda's urine, so the urine must be collected, packaged and couriered 70 miles to the lab to see how far the cycle has progressed.

On Monday, the level had been at baseline since Friday. "This is when we wait," zoo spokeswoman Pamela Baker-Masson said. It was still at baseline Tuesday.

For the zoo, this is a time of hope, and dread, officials said: hope that there could be another cub to replace the departed Tai Shan, who was sent to China in February; dread that there will be yet another failed attempt at pregnancy.

"It's heartbreaking when you get to the end and there's nothing there," said Janine L. Brown, head of the institute's endocrinology lab. "I kind of dread the end of today because it could be another . . . " Her voice trailed off.

The effort is even more intense because Mei Xiang and her mate, Tian Tian, could also soon be gone. Although the zoo hopes they can stay, they are here on a 10-year loan from China that expires in December.

Monday morning, panda keeper Mary Charlton packaged two vials of frozen urine, marked "MX" for Mei Xiang, into the scuffed Styrofoam container that the zoo has used for years to transport specimens.

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