Hormone-blocking implant halts too-early puberty

Sometimes, when hormones get out of kilter, young girls can enter puberty at too early an age - before they're even 7 or 8 years old and before they're ready to stop growing and begin sexual maturation. Now, an Israeli team has come up with a convenient way to stop the process.

They report that an implant containing histrelin, a potent inhibitor of gonadotropin-releasing hormone, is effective in treating central precocious puberty, as the condition is called.

"The histrelin implant consistently suppresses clinical and laboratory parameters of puberty for one year and is a promising new technique for treating central precocious puberty without the pain and inconvenience of monthly injections," write Dr. Irving M. Spitz from Shaare Zedek Medical Center, Jerusalem, and colleagues in the medical journal of Pediatrics.

Spitz's team investigated whether a histrelin implant would suppress gonadotropin and estradiol, hormones that bring on puberty and menstruation, in 11 girls with central precocious puberty for 12 months and compared the suppression to standard treatment.

There was no menstrual bleeding during the implant treatment, the authors report, and mean breast development regressed somewhat during treatment.

The acceleration in bone maturation that would signal an end to growth in height decreased during treatment, as did growth velocity, the report indicates.

Puberty hormones remained suppressed at nine months after implant insertion in all 11 girls, and up to 15 months in the six girls who returned late to have the implant removed, the researchers note.

All the girls reported less pain and discomfort and less interference with school activity and work with the implant than with standard monthly injections, the investigators report.

"A multicenter clinical trial is currently underway in the United States," Dr. Spitz told Reuters Health. "We are continuing to follow our Israeli patients, and we plan to study (normal hormone) recovery following implant removal at the completion of the course of treatment."

SOURCE: Pediatrics, December 2005.