Effects of progesterone on chemosensitivity in normal men.

Progesterone administration increase VE in man, but its effects on ventilatory response to hypercapnia and hypoxia have not been well documented. Accordingly, VE, HVR, and HCVR were measured during placebo and MPA administration in 11 normal men. The effect of MPA (20 mg orally q 8 hr for 32 hr) on T degrees, metabolic rate (VO2 and VCO2) was also determined. With MPA, T degrees, rose 0.4 degrees C +/- 0.0008 (S.E.M.) p less than 0.0001), VE increased 0.46 +/- 0.16 L/min (p less than 0.01), and VO2 and VCO2 did not change significantly. HCVR (measured under hyperoxic conditions during rebreathing) increased significantly (P less than 0.01) from 2.9 +/- 0.33 L/min/mm Hg (placebo) to 4.0 +/- 0.29 (MPA). HVR was measured as the shape parameter A, so that when A increased, HVR was augmented. During MPA, HVR increased from A = 132 +/- 19.1 to 179 +/- 20.5 (P less than 0.02). We conclude that 60 mg of MPA daily in normal men increases VE and chemosensitivity as measured by the ventilatory response to hypercapnia and hypoxia.