Comparison of growth hormone responses to growth hormone-releasing factor and clonidine in women with normal or poor ovarian response to gonadotropin stimulation.

OBJECTIVE

To assess the reliability of growth hormone (GH) secretion tests using provocative agents in women of different ovarian status.

DESIGN

Comparison of GH secretion in response to clonidine (Catapressan; Boehringer Ingelheim, Reims, France) and growth hormone-releasing factor (GH-RF).

SETTING

University Hospital, Hôpital Tenon, Paris, France.

PATIENTS

Women categorized as "normal" (n = 6) or "poor" responder (n = 7) to ovarian stimulation with gonadotropins, depending on the follicular development attained at previous IVF attempts.

INTERVENTIONS

Clonidine (0.300 mg administered orally) once and GH-RF (1 micrograms/kg IV) repeated twice. The tests were performed in random order in each individual on following cycles.

MAIN OUTCOME MEASURES

Basal and peak GH values, area under the curve (AUC).

RESULTS

Poor responder patients show significantly higher basal levels of FSH, GH, and insulin-like growth factor 1; FSH and basal GH levels are positively correlated. Peak GH levels and AUC are not significantly different in both categories of patients, whether GH-releasing factor or clonidine are used as provocative agents. True positive rate is 56.4% at the cutoff value of 7 micrograms/L, with no significant difference between the patients of the normally or poorly responding groups. At the 10-micrograms/L cutoff level, the true positive rate is almost half in the poor responder group (19.0% versus 38.9%), but the difference is not significant.

CONCLUSIONS

These results raise concern about using the GH secretory response to a single clonidine administration as a predictive test of the therapeutic benefit that could be obtained by co-stimulating the somatotropic axis during a treatment with gonadotropins in poor responder patients, especially when their FSH basal levels are elevated.