Multimedia Reporting (Kuhr-Musser)

A team of researchers working in Nairobi, Kenya, found that the stimulant khat increases testosterone levels in male baboons. The results may help the team understand how chewing khat, which is common in Africa, affects male hormones.

Khat is a leafy shrub grown in Africa and the Arabian peninsula. Its leaves contain cathonine, a mild stimulant to the central nervous system. Chewing khat has been a popular social activity in African countries for many generations- similar to having a drink or a cup of coffee with a friend, said Dr. Daudi Langat, research assistant professor at the University of Kansas Medical Center who was one of the researchers for this study.

Khat was introduced in the United States more recently by immigrants, and is sometimes used by people who need to stay awake for long periods of time on a job, according to the National Drug Intelligence Center.

The study was sponsored by a research grant from the World Health Organization Special Program for Research and Organization Training in Human Reproduction and conducted at the Institute of Primate Research in Kenya. The researchers, led by Dr. Jason Mwenda, wanted to investigate the effects of khat on human reproduction.
They did this by measuring changes in reproductive hormones. However, they didn’t use humans in their experimentation for ethical reasons. Instead, baboons were used as an animal model because the evolutionary development of baboons and humans are similar.

Five male baboons were given a 250 gram oral dose of khat juice weekly for eight weeks. The amount of the dose was based on personal accounts and interviews of male Kenyans who chew khat regularly, and was then adjusted for the weight of the animals, Mwenda said.

During the eight weeks when khat was administered, scientists also collected blood samples of the baboons on a weekly basis. The blood was later used for analysis of hormonal levels. The body weight of the baboons dropped as much as 10 percent in the two month testing period, and blood pressure increased by about 36 percent. The baboons were under anesthesia during this procedure, so no changes in behavior were observed. However, researchers said that the baboons had penile erections during the experiment, a result of higher testosterone levels from the khat.

Testosterone levels increased with the administration of khat and remained higher than normal for a month after the conclusion of the experiment before gradually returning to normal. Khat had a reverse effect on prolactin and cortisol levels, which decreased during the study and remained low for several weeks before returning to normal. Body weight returned to normal after about three months.

Langat said that several factors inhibited their research: a limited number of animals were examined over a short period of time. Thus, the scientists could only study short-term effects of the khat.

However, their findings provide important insight into the short-term effects that khat has on hormonal levels. They also suggest that this model of study may be a good way to study effects of khat on humans in the future.

Langat says the researchers hope to further investigate the findings from this research and to determine the long-term effects of khat use.