ohmidog!

An Arizona scientist trying to induce menopause in mice — the female of that species up to then had been missing out on that experience — has discovered a pill to sterilize dogs, one she says could eventually bring an end to surgical spaying.

Dr. Loretta Mayer was looking for a way to artificially induce menopause in mice so they could be used to study human diseases when she and another scientist developed a drug that they realized also could be used to sterilize female dogs, the Arizona Republic reports.

If approved by the FDA — a prospect that could take years — Chemspay, as it has been dubbed, could revolutionize veterinary medicine and go along way in reducing canine overpopulation in Arizona and nationwide, Mayer says.

ChemSpay can be administered by either a pill or injection.

Mayer hopes to eventually introduce the drug in Arizona and recently persuaded the state legislature to alter state law to allow animal shelters to use non-surgical means for sterilizing cats and dogs.

Mayer, 62, spent more than 20 years working in business before returning to school to pursue a master’s and doctorate in biology at Northern Arizona University. In 2000, she began her postdoctorate work at the University of Arizona, working under Dr. Patricia Hoyer, an ovarian toxicologist who was studying diseases common in aging women.

Mice, unlike women, never lose their reproductive capabilities. So Hoyer and Mayer developed a drug they dubbed “mouseopause” that induced menopause in female lab mice by eliminating eggs in the ovaries without surgery. The development allowed lab mice to be used as models for studying diseases associated with menopause.

In 2002, Mayer started a biotechnology company called SenesTech, studying how the drug could be used on other animals. She has tested it on animals in Indonesia, India, New Zealand and Australia and on the Navajo Reservation, at the request of the director of the tribal animal shelter.

“He said to me, ‘If you could do for a dog what you do for a mouse, I wouldn’t have to kill 400 animals a month,’ ” Mayer said.

Mayer and SenesTech administered the contraceptive to reservation dogs from 2004 to 2008.The trials proved that Chemspay reduced the number of eggs in the tested dogs significantly.

Last year, SenesTech became involved in a project that combines rabies vaccinations with fertility control for the feral-dog population in parts of India. Mayer will return to India this December to resume her work with the group.

Although Chemspay is about six to nine years away from being approved by the FDA, Mayer said she hopes to begin FDA-approved trials in about three years at the Second Chance Center for Animals in Flagstaff.

Mayer is not the first scientist to develop sterilizing drugs for animals. Neutersol, a sterilizing injection for male dogs, was approved by the FDA and tested in trials at the Arizona Humane Society a few years ago. It was taken off the market in 2005 because of a manufacturing disagreement and is now being marketed under another name. It is not currently available in the U.S.

(Photo: Martha Ellis / Arizona Republic)