The induction of premature luteolysis in normal women--follicular phase luteinizing hormone secretion and corpus luteum function in the subsequent cycle

Women with luteal phase deficiency have been shown to have an increased frequency of luteinizing hormone pulses in the early follicular phase of the menstrual cycle. Because progesterone is known to modulate luteinizing hormone secretion, it has been hypothesized that the decreased progesterone secretion in a previous luteal phase deficiency cycle could lead to the abnormal luteinizing hormone secretory pattern in the ensuing early follicular phase. With the possibility that the higher luteinizing hormone pulse frequency might lead to another deficient luteal phase, it becomes conceivable that luteal phase deficiency could be self-perpetuating. To test this hypothesis, luteal phase deficiency was induced in six normal women by decreasing luteinizing hormone support of the corpus luteum with a gonadotropin-releasing hormone antagonist Nal-Glu, administered twice daily beginning in the midluteal phase after a control cycle. During the antagonist-treated luteal phase, each subject met the predetermined criteria for induced luteal phase deficiency: a 33% or greater decrease in integrated progesterone from the control cycle and an integrated progesterone level less than 100 ng/ml per day. Luteinizing hormone secretion patterns were determined by frequent blood sampling performed every 10 minutes for 12 hours in the early follicular phase of the control cycle and the cycle after antagonist administration. Daily luteal progesterone levels were measured in the control, treatment, and posttreatment cycles. Each volunteer served as her own control. Standard parameters were compared between the control and posttreatment pulse studies in the early follicular phase: (1) luteinizing hormone pulse frequency was 9.5 +/- 1.0 vs 10.0 +/- 0.9 pulses/12 hours, control vs posttreatment, respectively, p = 0.5; (2) luteinizing hormone pulse amplitude was 11.0 +/- 1.3 vs 12.0 +/- 2.2 ng/ml, p = 0.6; and (3) luteinizing hormone mean level was 19.4 +/- 2.3 vs 22.2 +/- 3.3 ng/ml, p = 0.1. Corpus luteum function was also compared between the control and posttreatment cycles. Luteal phase length was 13.7 +/- 0.6 vs 12.7 +/- 0.6 days, p = 0.08. Integrated progesterone values were 136.9 +/- 12.9 vs 130.5 +/- 11.3 ng/ml per day, p = 0.5. Therefore no discernible abnormalities in early follicular luteinizing hormone secretions or corpus luteum secretion of progesterone occurred after an induced luteal phase deficiency cycle.(ABSTRACT TRUNCATED AT 400 WORDS)