| Popis: |
The reality of the interaction of GH and its mediator, IGF-I, with gonadotrophins is now established. The results of these studies and others have obvious implications, both physiologically and clinically. Co-treatment with GH augments the gonadal response to gonadotrophins, and it seems to be of particular value in patients who are poor responders to gonadotrophin treatment and who have pituitary hypofunction induced surgically, idiopathically (hypogonadotrophic hypogonadism) or medically (treatment with GnRH analogues). There is conflicting evidence as to whether the observed effect of GH is exerted directly on the ovary or mediated through IGF-I. Treatment with GH causes a distinct increase in serum IGF-I concentrations, which correlate with, but are always higher than, follicular fluid levels, suggesting that GH stimulates hepatic production of IGF-I and that the effect on the ovary is endocrine. Further research will, hopefully, clearly define the precise therapeutic role of GH in the induction of ovulation, the selection of the most appropriate group of patients to be treated, and the minimum dose of GH needed to sensitize the ovary. Further studies are also needed to explore the action of GH and to define the role of IGF-I in the process of follicular development. |
