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Yale University |
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Information provided by: | Yale University |
ClinicalTrials.gov Identifier: | NCT00589134 |
Women are at greater risk for exercise-induced hyponatremia (low blood sodium concentration) and this risk has been attributed to their lower body weight and size, excess water ingestion and longer racing times relative to men. While these factors contribute to the greater incidence of hyponatremia in women, it is likely that their greater levels of estradiol in plasma and/or tissue also play a role in increasing the risk of hyponatremia in women. More importantly, estradiol may also leave women more susceptible to the extreme consequences of hyponatremia (i.e. brain damage, death). Hyponatremia is generally attributed to inappropriately elevated levels of the hormone arginine vasopressin (AVP). AVP is the most important hormone controlling water retention in the kidney. Earlier studies in our laboratory have demonstrated that estradiol lowers the threshold for thirst sensation and AVP release during exercise. The purpose of these studies is to test the hypotheses that in women with a history of hyponatremia, estradiol lowers the thresholds for thirst and AVP release, leading to greater fluid retention, lower blood sodium concentration during endurance exercise in the heat. However, we further hypothesize that progesterone administration along with estradiol administration will attenuate the effect of estradiol on the regulation of thirst and AVP, normalize fluid retention, and serum sodium concentration during endurance exercise in the heat. In women without a history of hyponatremia, we expect that estradiol administration will lower the thresholds for thirst and AVP release, but will not increase fluid retention or reduce blood sodium concentration during endurance exercise in the heat. We hypothesize that progesterone administration along with estradiol administration will attenuate the effect of estradiol on thirst and AVP, but have no effect on fluid retention or serum sodium concentration during endurance exercise in the heat. To test these hypotheses, women will perform endurance exercise in the heat under three hormonal conditions: 1) during Gonadotropin-releasing hormone (GnRH) antagonist alone--which will suppress estradiol and progesterone; 2) during GnRH antagonist+estradiol; and 3) during GnRH antagonist+estradiol+ progesterone. During exercise, fluid will be replaced with either water or a carbohydrate-electrolyte beverage (random assignment).
Condition | Intervention |
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Exercise Induced Hyponatremia |
Dietary Supplement: Gatorade Endurance Formula Other: ganirelix acetate |
Study Type: | Interventional |
Study Design: | Basic Science, Randomized, Open Label, Active Control, Parallel Assignment, Efficacy Study |
Official Title: | The Effects of Estradiol and Progesterone on Arginine Vasopressin Regulation and Serum Sodium Concentration |
Estimated Enrollment: | 26 |
Study Start Date: | January 2006 |
Estimated Study Completion Date: | December 2009 |
Estimated Primary Completion Date: | December 2009 (Final data collection date for primary outcome measure) |
Arms | Assigned Interventions |
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1: Experimental
type of beverage
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Dietary Supplement: Gatorade Endurance Formula
carbohydrate electrolyte beverage
Other: ganirelix acetate
GnRH antagonist, subcutaneous injection, 0.25 mg/day for 21 days.
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Ages Eligible for Study: | 18 Years to 35 Years |
Genders Eligible for Study: | Female |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
Exclusion Criteria:
Contact: Nina Stachenfeld, PhD | 203-562-9901 ext 219 | nstach@jbpierce.porg |
Contact: Cheryl Leone, MA | 203-562-9901 ext 266 | cleone@jbpierce.org |
United States, Connecticut | |
John B. Pierce Laboratory | Recruiting |
New Haven, Connecticut, United States, 06519 | |
Principal Investigator: Nina Stachenfeld, PhD |
Principal Investigator: | Nina Stachenfeld, PhD | John B. Pierce Laboratory |
Responsible Party: | Gatorade Sports Science Institute ( Craig Horswill ) |
Study ID Numbers: | 188, 0508000538 |
Study First Received: | January 2, 2008 |
Last Updated: | February 13, 2009 |
ClinicalTrials.gov Identifier: | NCT00589134 History of Changes |
Health Authority: | United States: Institutional Review Board |
Metabolic Diseases Progesterone Hyponatremia Hormone Antagonists Estradiol valerate Hormones, Hormone Substitutes, and Hormone Antagonists Cardiovascular Agents Estradiol 17 beta-cypionate Hormones Hemostatics |
Estradiol Arginine Vasopressin Ganirelix Progestins Estradiol 3-benzoate Vasoconstrictor Agents Vasopressins Water-Electrolyte Imbalance Polyestradiol phosphate Metabolic Disorder |
Metabolic Diseases Coagulants Progesterone Hyponatremia Hormone Antagonists Hematologic Agents Physiological Effects of Drugs Hormones, Hormone Substitutes, and Hormone Antagonists Cardiovascular Agents Hormones Hemostatics |
Pharmacologic Actions Arginine Vasopressin Ganirelix Natriuretic Agents Progestins Therapeutic Uses Vasopressins Vasoconstrictor Agents Water-Electrolyte Imbalance Antidiuretic Agents |