Prolactin and growth hormone secretion after thyrotrophin-releasing hormone infusion and dopaminergic (DA2) blockade in infertile patients with minimal/mild endometriosis

BACKGROUND: The origin of infertility in patients with endometriosis without tubal occlusion has not yet been clearly defined. Several reports show an abnormal pituitary-ovarian axis in this group of patients. Moreover, prolactin (PRL) and growth hormone (GH) secretion is closely related to reproductive status. This study aimed to evaluate PRL and GH secretion after metoclopramide and thyrotrophin-releasing hormone (TRH) infusion in infertile patients with minimal/mild endometriosis. METHODS: A total of 64 women participated in the study: 33 fertile patients without endometriosis; 10 fertile patients with minimal/mild endometriosis; and 21 infertile patients with minimal/mild endometriosis. TRH or metoclopramide was administered randomly in two sequential menstrual cycles (cycle days 3-5). Serum PRL and GH secretion before and after dopaminergic type 2 (DA2) receptor blockade and TRH were compared. RESULTS: Higher serum PRL levels were observed in patients with endometriosis at baseline and after 15 and 30 min of TRH administration. Also, infertile patients with endometriosis had lower serum estradiol levels than fertile patients. Moreover, the dopaminergic blockade did not result in abnormal PRL or GH secretion. CONCLUSIONS: Decreased serum estradiol levels and altered PRL secretion after TRH administration in infertile patients with minimal/mild endometriosis are related to ovulatory dysfunction and infertility in this group of patients without tubal occlusion.