Objective: To investigate the effects of chronic administration of GnRH agonists (GnRH-a) on pituitary TSH and PRL secretion in adult women.
Design: Prospective case-controlled study.
Setting: Academic division of Reproductive Endocrinology, Department of Obstetrics and Gynecology.
Patients: Ten ovulatory women and 10 women treated with monthly depot injections of leuprolide acetate (3.75 mg) were studied.
Interventions: All subjects underwent pituitary stimulation with human thyrotropin-releasing hormone (TRH), 500 micrograms IV.
Main outcome measures: Basal and post-TRH-stimulated serum levels of TSH and PRL at 15, 30, 45, 60, 90, 120, and 180 minutes were compared among the two groups. Also, basal of T4, triiodothyronine, and triiodothyronine resin uptake studies were obtained and compared among the GnRH-a-treated and control groups.
Results: No statistically significant difference between baseline or TRH-stimulated serum TSH and PRL could be detected between control and GnRH-a-treated groups of women. Furthermore, these groups were similar with respect to routine thyroid function assays.
Conclusion: Gonadotropin-releasing hormone agonist does not significantly affect baseline or TRH-stimulated TSH and PRL levels nor basal serum T4 and triiodothyronine levels or triiodothyronine resin uptake in adult women.