The hypothalamic-pituitary-luteal axis in women: Effects of long-term orally active opioid antagonist (naltrexone) administration
Aim of our study is to assess the effect of a long-term oral opiate antagonist treatment during the luteal phase on the hypothalamic-pituitary-ovarian axis. Fourteen normovulatory women partecipated to the study. Immediately after the ovulation, the patients were randomly divided in two groups: in the first one women received naltrexone 50 mg/die orally (Antaxone Zambon Italy) from day 1 of the luteal phase for 7 days. In the second patients were treated with placebo for the same period and served as control group. On day 7, patients were hospitalized for a pulse pattern study followed by a GnRH test. LH, FSH, Estradiol, Progesterone were assayed. The naltrexone administration strongly increased the number as well as the amplitude of the gonadotropin pulses. The circulating P levels were also significantly higher in treated patients. The GnRH injection significantly increases the gonadotropin secretion in all patients. The stimulated LH and FSH secretion was significantly greater in treated patients when compared to controls. Such discharge of LH determined a significant increase of progesterone production in controls, but failed to stimulate the corpus luteum in treated patients. In conclusion the present paper strengtheen an important role of the opioidergic system in the regulation of GnRH pulsatility in luteal phase. Moreover, our findings confirms the sensibility of the corpus luteum to LH and the possibility to stimulate the P secretion during the luteal phase.
Key-wordsLH pulsatility luteal phase naltrexone progesterone secretion
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- 14.Caruso A., Fulghesu A.M., Di Simone N., Fortini A., Lanzone A., Mancuso S. Failure of progesterone response to GnRH in hypoprolactinemic women. Infertility 13: 181, 1992.Google Scholar
- 16.Guardabasso V., Oerter K.E., Lademarco M.F., Veldhuis J.D., Rodbard. D. In: Laboratory of Theoretical and Physical Biology, (eds.). DETECT’s user guide. Bethesda (MD): National Institutes of Health, 1988.Google Scholar
- 18.Inaudi P., Reymond M.J., Rey F., Genazzani A.D., Lemarchand-Beraud T. Pulsatile secretion of gonadotropins and prolactin during the follicular and luteal phases of the menstrual cycle: analysis of instantaneous secretion rate and secretory concomitance. Fertil. Steril. 58: 51, 1992.PubMedGoogle Scholar
- 19.Genazzani A.D., Petraglia F., Volponi C., D’Ambrogio G., Facchinetti F., Genazzani A.R. FSH secretory pattern and degree of concordance with LH in amenorrheic, fertile and postmenopausal women. Am. J. Physiol. 264 (Endocrinol. Metab. 27), E1–E6, 1993.Google Scholar
- 24.Leyendecker G., Wildt L., Hansmann M. Pregnancies following chronic intermittent (pulsatile) administration of GnRH by means of a portable pump (zyklomat): a new approach in the treatment of infertility in hypothalamic amenorrhea. J. Clin. Endocrinol. Metab. 51: 1214, 1980.PubMedCrossRefGoogle Scholar