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The Effects of Estradiol and Progesterone on Arginine Vasopressin Regulation and Serum Sodium Concentration

This study has been completed.
Sponsor:
Information provided by:
Yale University
ClinicalTrials.gov Identifier:
NCT00589134
First received: January 2, 2008
Last updated: July 15, 2010
Last verified: July 2010
  Purpose

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
Exercise Induced Hyponatremia
Dietary Supplement: Gatorade Endurance Formula
Other: ganirelix acetate

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Basic Science
Official Title: The Effects of Estradiol and Progesterone on Arginine Vasopressin Regulation and Serum Sodium Concentration

Resource links provided by NLM:


Further study details as provided by Yale University:

Primary Outcome Measures:
  • osmotic regulation of AVP [ Time Frame: 3 years ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • temperature responses [ Time Frame: 3 years ] [ Designated as safety issue: No ]

Enrollment: 26
Study Start Date: January 2006
Study Completion Date: December 2009
Primary Completion Date: December 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: 1
type of beverage
Dietary Supplement: Gatorade Endurance Formula
carbohydrate electrolyte beverage
Other Name: Gatorade Endurance Formula
Other: ganirelix acetate
GnRH antagonist, subcutaneous injection, 0.25 mg/day for 21 days.
Other Name: Antagon

  Eligibility

Ages Eligible for Study:   18 Years to 35 Years
Genders Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • healthy volunteers (18-35 yrs) with and without previous exercise induced hyponatremia

Exclusion Criteria:

  • conditions that would preclude safe exercise or safe use of hormones
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00589134

Locations
United States, Connecticut
John B. Pierce Laboratory
New Haven, Connecticut, United States, 06519
Sponsors and Collaborators
Yale University
Investigators
Principal Investigator: Nina Stachenfeld, PhD John B. Pierce Laboratory
  More Information

No publications provided

Responsible Party: Craig Horswill, Gatorade Sports Science Institute
ClinicalTrials.gov Identifier: NCT00589134     History of Changes
Other Study ID Numbers: 188, 0508000538
Study First Received: January 2, 2008
Last Updated: July 15, 2010
Health Authority: United States: Institutional Review Board

Additional relevant MeSH terms:
Diabetes Insipidus
Hyponatremia
Endocrine System Diseases
Kidney Diseases
Metabolic Diseases
Pituitary Diseases
Urologic Diseases
Water-Electrolyte Imbalance
Arginine Vasopressin
Ganirelix
Progesterone
Vasopressins
Antidiuretic Agents
Cardiovascular Agents
Coagulants
Hematologic Agents
Hemostatics
Hormone Antagonists
Hormones
Hormones, Hormone Substitutes, and Hormone Antagonists
Natriuretic Agents
Pharmacologic Actions
Physiological Effects of Drugs
Progestins
Therapeutic Uses
Vasoconstrictor Agents

ClinicalTrials.gov processed this record on November 20, 2014