Endocrinology: The role of luteinizing hormone in human follicle development and oocyte fertility: evidence from in-vitro fertilization in a woman with long-standing hypogonadotrophic hypogonadism and using recombinant human follicle stimulating hormone

To evaluate the relative importance of follicle stimulating hormone (FSH) and luteinizing hormone (LH) in follicular development and oocyte fertility in the human species, the use of recombinant human FSH, human menopausal gonadotrophin (HMG), and very highly purified urinary human FSH (FSH-HP) plus oestradiol valerate for ovarian stimulation and in-vitro fertilization (IVF) were compared in three cycles in a woman with isolated congenital gonadotrophin deficiency who had never been treated with ovarian stimulating agents. The total number of ampoules of gonadotrophins used was lower in the HMG treatment cycle. Ovarian response and IVF outcome in the three treatment cycles were as follows: (i) HMG cycle: normal follicular growth, normal pattern of oestradiol and inhibin through the menstrual cycle, high fertilization rate (93%); (ii) recombinant FSH cycle: normal follicular growth, low oestradiol and abnormal inhibin, finally poor rate of fertilization (28%); (iii) FSH-HP plus oestradiol valerate cycle: normal follicular growth, normal pattern of inhibin and poor fertilization rate (27%). Luteal plasma progesterone concentrations were much higher in the HMG treatment cycle. This case shows that FSH is the only factor required in order to induce follicular growth in the human, although LH or a product derived from its action may assist in order to achieve full follicular maturity and oocytes capable of fertilization. Though oestradiol might have a mediatory role in the process of follicular maturation, our results favour a direct primary role of LH in complete maturation of the follicle.