Effect of an OT antagonist on the control of the midcycle LH surge in women

• Published in: Clinical endocrinology (Oxford) 2009-07, Vol.71 (1), p.100-103
• Main Authors: Vanakara, P., Dafopoulos, K., Papastergiopoulou, L., Kallitsaris, A., Papageorgiou, I., Messinis, I. E.
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Endocrinopathies; Female; Fundamental and applied biological sciences. Psychology; Hormone Antagonists - administration & dosage; Humans; Luteinizing Hormone - secretion; Medical sciences; Ovarian Follicle - drug effects; Ovarian Follicle - secretion; Oxytocin - antagonists & inhibitors; Vasotocin - administration & dosage; Vasotocin - analogs & derivatives; Vertebrates: endocrinology; Young Adult
• ISSN: 0300-0664; 1365-2265
• DOI: 10.1111/j.1365-2265.2008.03456.x

Summary Objective  Data in women regarding the role of OT in LH secretion during the LH surge are conflicting. As in previous studies blood samples for LH measurements were taken infrequently, we re‐examined this matter in women with a fully characterized midcycle LH surge. Design  Normal women were studied over two cycles. When the dominant follicle reached a diameter of either 16–17 mm (Group 1) or 18–19 mm (Group 2), the women were infused intravenously for 3 h with normal saline (cycle‐1) or atosiban (cycle‐2). Patients  Fifteen women (10 in group 1 and 5 in group 2) aged 23–35 years. Measurements  Blood samples were obtained every 6 h to characterize the midcycle LH surge. Results  The time interval (mean ± SEM) from the start of the infusion to the onset of the LH surge in the two cycles was 46·8 ± 4·8 and 45·6 ± 9·6 h in group 1 and 6·0 ± 2·4 and 7·5 ± 2·8 h, respectively, in group 2. LH values during the LH surge were similar in the two cycles except in group 1 at the point of 30 h at which LH value in cycle‐2 (41·2 ± 4·6 mIU/ml) was significantly lower than in cycle‐1 (52·8 ± 3·4 mIU/ml, P