Ovarian sensitization to gonadotrophins by human growth hormone. Persistence of the effect beyond the treated cycle.

OBJECTIVE

To document the persistence of a sensitizing effect of human growth hormone on the ovarian responsiveness to human menopausal gonadotrophin in anovulatory patients resistant to standard gonadotrophin doses.

DESIGN

We performed an open study of three patients given 4, 12 or 24 IU recombinant growth hormone on alternate days for 5-7 doses, concomitantly with gonadotrophin, and assessed gonadotrophin dose requirements before, during and after the cycle of growth hormone therapy.

PATIENTS: We studied two with isolated gonadotrophin deficiency and primary amenorrhoea and one with a pituitary tumour and hyperprolactinaemia which normalized with bromocriptine but in whom there was persisting secondary amenorrhoea.

MEASUREMENTS: We measured body mass index, FSH, LH, prolactin, growth hormone, insulin-like growth factor I (IGF-I), oestradiol and inhibin at baseline and growth hormone, IGF-I, oestradiol and inhibin during treatment. In addition we noted the numbers of ampoules (75 IU) and the last pre-hCG dose of gonadotrophin used before, during and after growth hormone therapy.

RESULTS

Baseline growth hormone levels were low but IGF-I levels were normal. IGF-I increased by 20% in the subject given 4 IU growth hormone, and by 50-100% in the other two. Pretreatment daily gonadotrophin dosage of 8-11 ampoules pre-hCG was reduced to 3-6 ampoules during growth hormone and 3-4 post growth hormone. This effect persisted for 4 cycles over 7 months in one subject.

CONCLUSION

Growth hormone causes persisting ovarian sensitization to gonadotrophin and may produce a substantial lowering of gonadotrophin requirement for ovulation induction in patients with large dosage needs.