A hormone-free drug tested in male mice might someday prove viable for men who want their own birth-control pill, according to new research.
The compound stifles sperm production but not sexual activity, fertility returns once treatment stops and males can go on to father healthy offspring, the researchers say.
Strictly speaking, the new drug is not yet a male "pill," explained lead researcher Dr. James Bradner, of the Dana-Farber Cancer Institute and Harvard Medical School in Boston.
"The molecule used in this study, JQ1, is a prototype drug," Bradner said, explaining it is not intended for human use. "We have successfully administered the agent to animals by mouth, but notably in this research, JQ1 was injected into the belly of the mice and rats studied."
JQ1 works by targeting a protein called BRDT that functions in the testes and is vital for fertility. Unlike previous drugs, JQI can physically reach the cells that make sperm. Sperm cell production drops in number and surviving sperm don't work as well.
Researchers injected the rodents over an 18-month period and found they were mating as much as ever, but were completely infertile at higher does of JQ1. After treatment ended, they were again able to sire apparently healthy offspring.
"Mice can only report a few obvious symptoms," Bradner said, "but with that caveat we do not observe any developmental or behavioral effects on offspring."
The results have implications for men as well as mice.