Effects of progesterone on chemosensitivity in normal men

Area of Science:

• Physiology
• Respiratory Medicine
• Endocrinology

Background:

• Progesterone is known to increase resting ventilation in humans.
• However, its precise effects on the ventilatory response to hypercapnia and hypoxia require further documentation.

Purpose of the Study:

• To investigate the impact of medroxyprogesterone acetate (MPA) on resting ventilation, and ventilatory responses to hypercapnia and hypoxia in healthy men.
• To assess the effects of MPA on body temperature and metabolic rate.

Main Methods:

• 11 healthy men received either a placebo or MPA (20 mg orally every 8 hours for 32 hours).
• Ventilatory equivalents (VE), hypoxic ventilatory response (HVR), and hypercapnic ventilatory response (HCVR) were measured.
• Body temperature, oxygen consumption (VO2), and carbon dioxide production (VCO2) were also determined.

Main Results:

• MPA administration led to a significant increase in body temperature (0.4°C).
• Resting ventilation (VE) increased significantly (0.46 L/min) with MPA.
• Both hypercapnic ventilatory response (HCVR) and hypoxic ventilatory response (HVR) showed significant augmentation during MPA administration.

Conclusions:

• Daily administration of 60 mg MPA in healthy men significantly increases resting ventilation.
• MPA enhances chemosensitivity, as evidenced by augmented ventilatory responses to both hypercapnic and hypoxic challenges.