title: Menstrual cycle effects on the neurohumoral and autonomic nervous systems regulating the cardiovascular system.
abstract: Gonadal hormones may affect homeostatic mechanisms regulating the cardiovascular system. We investigated this relationship at five different crucial hormonal time points along the menstrual cycle. Eight eumenorrheic healthy subjects underwent a battery of autonomic tests, hemodynamics, and volume-regulatory hormone measurements. Fluid-regulatory hormones, plasma renin activity, and aldosterone increased along the luteal phase (P = 0.003 and 0.02, respectively), whereas rest supine-corrected hematocrit declined in the course of the menstrual cycle (P = 0.001). Plasma norepinephrine decreased from 1.4 +/- 0.2 to 0.95 +/- 0.1 nmol/liter (P < 0.02) [early follicular (EF) to late follicular]. Thereafter, concentrations gradually returned to EF levels. Lf to Hf domain ratio (spectral analysis of electrocardiogram) showed a difference from that of norepinephrine. The cardiovagal baroreflex sensitivity increased significantly along the luteal phase (P = 0.04). The dose of isoproterenol required to increase heart rate (HR) 15 beats per minute was 0.19 +/- 0.04 microg during the EF time point, and it increased to 0.39 +/- 0.06 microg during the late luteal time point (P = 0.05). However, blood pressure, HR, and their responses to orthostatic stress remained unchanged. Fluctuations in the ovarian hormones along the menstrual cycle are associated with unchanged blood pressure and HR, despite the significant variations in the different homeostatic mechanisms regulating the cardiovascular system.
authors.affiliation: Jacob Recanati Autonomic Dysfunction Center, Department of Medicine "C", Rambam Medical Center, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Nir
authors.initials: N
authors.lastname: Hirshoren
authors.forename: Inna
authors.initials: I
authors.lastname: Tzoran
authors.forename: Igor
authors.initials: I
authors.lastname: Makrienko
authors.forename: Yehuda
authors.initials: Y
authors.lastname: Edoute
authors.forename: Mikahl M
authors.initials: MM
authors.lastname: Plawner
authors.forename: Joseph
authors.initials: J
authors.lastname: Itskovitz-Eldor
authors.forename: Giris
authors.initials: G
authors.lastname: Jacob
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology*; D017704:Baroreflex / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects; D002320:Cardiovascular Physiological Phenomena; D005260:Female; D006329:Heart Conduction System / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008597:Menstrual Cycle / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D010953:Plasma Volume
chemical_list: D000318:Adrenergic beta-Agonists; D018377:Neurotransmitter Agents; D007545:Isoproterenol