Pituitary down-regulation with a single depot-dose of a GnRH agonist (triptorelin) in postmenopausal women

Gonadotropin levels were determined in 17 postmenopausal women before and after administering a single depot-dose of the GnRH agonist triptorelin. E2 levels of all samples were in the normal (low) postmenopausal range and no differences were found when the patients were grouped according to chronological age, or time after menopause. Pre-GnRH agonist levels of LH and FSH were in the normal (high) postmenopausal range. Two weeks after medication, LH and FSH had decreased to premenopausal levels (P < 0.0001). Eight weeks after medication, LH levels were still low whereas FSH levels had risen significantly again (P < 0.0001). Both LH and FSH levels, however, were still significantly below the serum concentrations before the administration of triptorelin (P < 0.0001). The pre-GnRH agonist level of FSH was significantly higher in women > 67 years old (P < 0.05), as compared to women < 67 years. Two weeks after medication both LH and FSH levels were significantly higher in women more than 15 years after menopause (P < 0.05), as compared to those < 15 years. The same was found for FSH in women > 67 years old. No further significant differences were noted. This study demonstrates a significant decrease of LH and FSH serum levels in postmenopausal women within two weeks after administration of a single depot-dose of the GnRH agonist triptorelin. After eight weeks, in contrast to premenopausal women, both LH and FSH, although rising, were still significantly suppressed.