EVALUATION OF THE IMPACT OF CONCURRENT GONADOTROPIN-RELEASING-HORMONE(GNRH) ANTAGONIST ADMINISTRATION ON GNRH AGONIST-INDUCED GONADOTROPE DESENSITIZATION
Eh. Illions et al., EVALUATION OF THE IMPACT OF CONCURRENT GONADOTROPIN-RELEASING-HORMONE(GNRH) ANTAGONIST ADMINISTRATION ON GNRH AGONIST-INDUCED GONADOTROPE DESENSITIZATION, Fertility and sterility, 64(4), 1995, pp. 848-854
Objective: To evaluate the impact of chronic GnRH antagonist therapy o
n the extent of GnRH agonist-induced gonadotrope desensitization. Desi
gn: Prospective and controlled. Setting: Primate Research Center. Part
icipants: Six reproductive age cycling female baboons (Papio cyanoceph
alus anubis). Interventions: The animals were divided into two groups.
Group A received a total of 19 pulses of 0.83 mu g/kg leuprolide acet
ate (LA) on a 12-hour dosing schedule. Group B received Nal-Lys (3 mg/
kg then 1 mg/kg every other day) for 1 week and then added an identica
l 19 pulses of LA while continuing Nal-Lys therapy. Main Outcome Measu
res: Characterization of the gonadotropin response was done by collect
ing serum samples at -15, 0, 15, 30, 60, 90, 120, 240, and 480 minutes
relative to the injection of the LA. Results: After equivalent baseli
ne responses, the baboons pretreated with Nal-Lys had an increased LH
and FSH response to the administration of the LA. After a total of 19
pulses of the LA, the Nal-Lys-treated animals had an increased FSH res
ponse in comparison to the untreated controls. This indicates that the
extent of gonadotrope desensitization was reduced in the presence of
the GnRH antagonist. Conclusions: The presence of GnRH antagonist redu
ces the extent of gonadotrope desensitization in response to the admin
istration of repetitive pulses of GnRH agonist.