The antiprogestin RU486 delays the midcycle gonadotropin surge and ovulation in gonadotropin-releasing hormone-induced cycles
| Autor: | George R. Merriam, Tannia P. Cartledge, Ann W. Zellmer, D. Lynn Loriaux, Lynnette K. Nieman, Marcelo C. Batista |
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| Rok vydání: | 1994 |
| Předmět: |
Adult
Ovulation endocrine system medicine.medical_specialty Time Factors medicine.drug_class medicine.medical_treatment media_common.quotation_subject Hypothalamus Gonadotropin-releasing hormone Biology Hypothalamic disease Gonadotropin-Releasing Hormone Placebos Ovarian Follicle Internal medicine Follicular phase Steroid hormone secretion medicine Outpatient clinic Animals Humans Gonadal Steroid Hormones Amenorrhea Menstrual Cycle media_common Obstetrics and Gynecology medicine.disease Mifepristone Endocrinology Reproductive Medicine Ovulation induction Female Gonadotropin Progestins hormones hormone substitutes and hormone antagonists |
| Zdroj: | Fertility and sterility. 62(1) |
| ISSN: | 0015-0282 |
| Popis: | Objective To investigate whether the antiprogestin RU486 acts primarily on the hypothalamus to delay the midcycle gonadotropin surge and thus gain insight into the site(s) of action of P in the control of ovulation. Design Prospective, crossover, single-blinded clinical study. Setting Outpatient clinic in an academic research environment. Patients Women with hypothalamic amenorrhea. Interventions RU486 or a placebo was given orally at a low dose of 1 mg/d for 5 days, starting when the dominant follicle reached 14 to 16 mm, to women with hypothalamic amenorrhea undergoing ovulation induction with GnRH pulses of unvarying frequency and dose. Blood samples and ovarian ultrasounds were obtained daily in the late follicular phase and every 3 to 4 days in the remainder of the cycle. Main Outcome Measures Follicular diameter and plasma levels of LH, FSH, E2, and P. Results RU486 consistently delayed the timing of the midcycle gonadotropin surge and ovulation. Gonadotropin and steroid levels were suppressed during RU486 treatment, but follicular growth progressed normally in most patients. conclusions RU486 does not act primarily on the hypothalamus to delay ovulation. Rather, this compound appears to antagonize P at the pituitary level to suppress gonadotropin and steroid hormone secretion. P may thus act on the pituitary, independent of any hypothalamic effects, to regulate the timing of the midcycle gonadotropin surge and ovulation. |
| Databáze: | OpenAIRE |
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