Effects of a potent LHRH-agonist on the pituitary gonadal axis with and without testosterone substitution.

In this study we investigated the effect of low and high dosages of a potent LHRH agonist on the pituitary-gonadal axis with special consideration to the effect on the tubular compartment of the testis. Included were 3 treatment groups: the probands in Group I were treated with 3 X 50 micrograms HOE 766/week intranasally for 5 months; in Group II with 3 X 100 micrograms HOE 766 intranasally/day for 6 months and in Group III with 3 X 200 micrograms HOE 766 intranasally plus 5 mg fluoxymesterone orally/day for 5 months. With the low dose (Group I) no changes in the seminal parameters measured could be observed whereas LH and FSH levels increased in plasma, testosterone showed no change compared to pretreatment values. When high dosages/day of a potent LHRH agonist were administered without androgen replacement (Group II) pronounced decrease of LH and FSH took place, the testosterone plasma levels approached the female range. Spermatogenesis was arrested. The agonist plus androgen replacement (Group III) counteracted the suppression of spermatogenesis.