Chemicals curbing male reproductive capacity

By Bill Scanlon, Rocky Mountain News (Contact)

Originally published 04:49 p.m., February 5, 2008
Updated 04:49 p.m., February 5, 2008

A half century of herbicides, chemicals and pollution have weakened the reproductive capacity of males — be they frogs, horses or humans, a Colorado State University researcher says.

Sperm counts are dropping about 1 percent a year; testicular cancer in young men has tripled in 50 years; male frogs aren't developing the voice boxes they need to attract mates.

Exposure to chemicals, in products from nail polish to pesticides, "can do permanent damage," particularly if the male is exposed in the womb, as a newborn or as an adolescent, said Rao Veeramachaneni, a biomedical sciences professor at CSU's College of Veterinary Medicine and Biomedical Sciences.

He points to the post-World War II boom in the use of chemicals and fertilizers as the beginning of the troubles for males in the Western World and across the planet.

Some of the chemicals can survive for 30 to 40 years, polluting rivers, lakes and groundwater, he noted.

Swallowed, they can attach to receptors in the body that help hormones do their jobs. They can either block actual hormones from attaching or they can mimic real hormones, causing confusion in the male body, or blocking the production of natural hormones.

Chemicals known as phthalates, used in cosmetics, upholstery, drugs and other products, are found in the urine, blood and breast milk of people, especially in the developed world, he said.

In studies funded by the Environmental Protection Agency, Veeramachaneni and his graduate students discovered that exposing tadpoles to dibutyl phthalate drastically slows their growth and ability to reproduce.

The use of DDT to help combat a resurgence of malaria in Africa has been associated with testicular cancer and infertility in wildlife there, he said.

Veeramachaneni and associate Carol Moeller used electron microscopic studies to show that when human sperm is exposed to seemingly innocuous chemicals it can become malformed or dysfunctional.

Noting that a third of the U.S. male population reports erectile dysfunction, Veeramachaneni is exploring a possible link with a fungicide commonly used in farming, vinclozolin.

In lab tests, he and researcher Jennifer Palmer found that some male offspring of animals exposed to the chemical during pregnancy displayed a complete lack of interest in females of the species.

Pollution, stress, smoking and multiple abortions are all leading to a rise in infertility in China, which may affect up to one-tenth of Chinese couples, Xinhua news agency said on Monday.

The Chinese government last year blamed pollutants, stress and smoking on a rising tide of infertility in the country, and a drop in sperm count since the 1970s.

Smoking marijuana also has been connected to a low sperm count.

scanlon@RockyMountainNews.com or 303-954-2897