Pituitary function is altered during the same cycle in women with polycystic ovary syndrome treated with continuous or cyclic oral contraceptives or a gonadotropin-releasing hormone agonist
Ruchhoft, E.A.; Elkind-Hirsch, K.E.; Malinak, R.
Fertility and Sterility 66(1): 54-60
1996
ISSN/ISBN: 0015-0282 PMID: 8752611 DOI: 10.1016/s0015-0282(16)58387-3Document Number: 298037
Clinical researchers recruited 16 women aged 16-41 diagnosed with polycystic ovary syndrome (PCOS) for a study designed to compare their pituitary responsiveness to exogenous gonadotropin releasing hormone (GnRH) stimulation after three months of therapy with either the continuous or cyclic regimen of combined oral contraceptives (OCs). The three treatments included six women on continuous therapy (i.e., every day for 3 months) with an OC containing 30 mcg ethinyl estradiol and 150 mcg desogestrel, six women on cyclic therapy (i.e., 21 days of OC therapy with 7 days of placebo over 3 months) with the same OC formulation, and four women on therapy with a GnRH agonist (GnRH-a), Lupron depot (3.75 mg leuprolide acetate). Luteinizing hormone (LH) levels fell significantly in all groups between baseline and three months treatment (p 0.001). Cyclic OCs exerted a less effective LH suppression than the continuous OC and the GnRH-a, however (88% vs. 99%; p 0.05). Only the cyclic OC group experienced a significant increase in LH after 5-7 days of placebo treatment (126% increase; p 0.008). The percent change in LH levels was significantly different between the cyclic and continuous OC groups (p 0.03) and between the cyclic OC and GnRH-a groups (p 0.01). Similarly, the cyclic OC group had an increase in testosterone levels after 5-7 days of placebo treatment (86% increase), while the other two groups had no change. When both the cyclic and continuous OC groups received their first GnRH stimulation test on days 15-17 of the third 28-day cycle and on days 26-28 (5-7 days of placebo in the OC cyclic group), the LH area under the curve (AUC) measurements were much greater in the cyclic OC group than the continuous OC and the GnRH-a groups (p 0.004). This event suggests increased pituitary sensitivity in patients receiving cyclic OCs regardless of the phase of the treatment cycle; which may be secondary to increased pituitary stores of LH in women with PCOS. These findings support the theory that LH contributes greatly to ovarian testosterone secretion in women with PCOS.