Effects of recombinant human follicle stimulating hormone on cultured human granulosa cells: comparison with urinary gonadotrophins and actions in preovulatory follicles

Herbimycin, a tyrosine kinase inhibitor with Src selectivity, reduces progesterone and estradiol secretion by human granulosa cells

The purpose of the present study was to investigate whether the tyrosine kinase inhibitor herbimycin with some selectivity to block Src would alter the stimulatory effects of follicle-stimulating hormone (FSH) and cyclic adenosine monophosphate (cAMP) on estradiol secretion by human granulosa cells. Granulosa cells were taken from ovaries of premenopausal women undergoing oophorectomy for reasons unrelated to ovarian pathology. Granulosa cells from follicles ranging from 5-20 mm in diameter were subjected to culture. Granulosa cells were cultured with human FSH (2 ng/mL) or cAMP (0-1 mM) and testosterone (1 microM) in the presence and absence of herbimycin (0-2 pM). Media were collected at 24, 48, and 72 h. Accumulation of cAMP, progesterone, and estradiol in the media was determined by radioimmunoassay. Herbimycin dose dependently inhibited the ability of FSH to induce increases in progesterone and estradiol secretion. Although herbimycin increased (p < 0.0001) the accumulation of cAMP in response to FSH, this was evident only at the high concentrations of herbimycin (2 microM). To determine whether herbimycin would inhibit the ability of exogenous cAMP to induce estradiol and progesterone secretion, granulosa cells were incubated with 0-1 mM cAMP in the presence and absence of various doses of herbimycin. Herbimycin inhibited cAMP-induced estradiol and progesterone secretion in granulosa cells. The results from seven experiments indicate that herbimycin inhibits FSH stimulation of estradiol and progesterone secretion and that this inhibition may be, in part, at post-cAMP site(s).

Mathematical model of FSH-induced cAMP production in ovarian follicles

During the terminal part of their development, ovarian follicles become totally dependent on gonadotropin supply to pursue their growth and maturation. Both gonadotropins, follicle-stimulating hormone (FSH) and luteining hormone (LH), operate mainly through stimulatory G protein-coupled receptors, their signal being transduced by the activation of the enzyme adenylyl cyclase and the production of second-messenger cAMP. In this paper, we develop a mathematical model of the dynamics of the coupling between FSH receptor stimulation and cAMP synthesis. This model takes the form of a set of nonlinear, ordinary differential equations that describe the changes in the different states of FSH receptors (free, bound, phosphorylated, and internalized), coupling efficiency (activated adenylyl cyclase), and cAMP response. Classical analysis shows that, in the case of constant FSH signal input, the system converges to a unique, stable equilibrium state, whose properties are here investigated. The system also appears to be robust to nonconstant input. Particular attention is given to the influence of biologically relevant parameters on cAMP dynamics.

Isoforms of human recombinant follicle-stimulating hormone: comparison of effects on murine follicle development in vitro

The effects of three isoforms derived from recombinant human FSH on ovarian follicle development in vitro were characterized for the first time. The three subfractions comprised discrete pI ranges of 3. 6-4.6 (acid), 4.5-5.0 (mid), and 5.0-5.6 (least acidic). Follicular growth, estradiol secretion, and antral formation were assessed for each fraction of isoforms in a range of concentrations over a 5-day culture period. Least acidic FSH produced, at and above 1.5 ng/ml, a high percentage of follicles growing above the size threshold necessary for antral formation, whereas mid and acid FSH induced similar growth only at higher concentrations (7.5 ng/ml and 50 ng/ml, respectively). Least acidic FSH specifically induced the most rapid growth of follicles during preantral development. Acid FSH at all concentrations stimulated estradiol-17ss secretion later during culture and antral formation in a lower proportion of follicles than did least acidic and mid FSH. It can be concluded 1) that the least acidic isoform induced fastest preantral growth, producing the largest antral follicles at the lowest dose of all three fractions and 2) that the less and mid acidic isoforms had more impact on stimulation of estradiol production and antral formation than the acid isoform.

Follicular development and hormonal levels following highly purified or recombinant follicle-stimulating hormone administration in ovulatory women and WHO group II anovulatory infertile patients

PURPOSE

Our purpose was to compare ovarian performance and hormonal levels, after ovulation induction, in both normal ovulatory women undergoing intrauterine insemination (group 1) and World Health Organization (WHO) group II anovulatory infertile patients (group 2), using two different gonadotropin drugs.

METHODS

Patients (n = 20 per group) were treated during consecutive cycles, using the same stimulation protocol, with highly purified urinary FSH (HP-FSH) in the first treatment study cycle and recombinant FSH (rFSH) in the second one. Patients in group 1 were treated according to a late low-dose technique, and WHO group II anovulatory patients (group 2) received chronic low-dose FSH therapy.

RESULTS

Compared with HP-FSH, treatment with rFSH in group 2 required significantly less ampules of drug to induce follicular development but resulted in significantly higher plasma levels of estradiol and inhibin A on the day of human chorionic gonadotropin injection. No differences were found when both treatment modalities were compared in group 1.

CONCLUSIONS

rFSH is more efficacious than urinary HP-FSH for ovulation induction in WHO group II anovulatory infertile patients as assessed by follicular development, hormonal levels, and the amount of FSH required.