We administered chlormadinone acetate (CMA), medroxyprogesterone acetate (MPA), and placebo to 16 normal male subjects using a randomized double-blind crossover study. After CMA administration, minute alveolar ventilation increased by +1.04 ± 0.22 (SE) l/min (P < 0.05) accompanied by decrements of arterial Pco2 (-4.0 ± 1.0 Torr) (P < 0.01) and [HCO3-] (-2.1 ± 0.05 mM/l (P < 0.01). On the other hand, in the MPA runs the corresponding changes of the above parameters were +0.71 ± 0.21 l/min (P < 0.05), -2.9 ± 0.6 Torr (P < 0.01), and -1.3 ± 0.3 mM/l (P < 0.01), respectively. The slopes of hypoxic ventilatory and occlusion pressure response lines remained unchanged in hypocapnia after CMA or MPA ingestion, but they increased when endtidal Pco2 was adjusted to the predrug level. The hypercapnic ventilatory and occlusion pressure response lines merely shifted to the left without changing their slopes with these agents. No significant differences in all the above parameters were found between CMA and MPA runs. We concluded that in the normal males the effect of CMA on ventilation was similar to that of MPA, despite the fact that the luteinizing activity of CMA was reported to be ~10 times higher than the latter.
|Number of pages||6|
|Journal||Journal of Applied Physiology|
|Publication status||Published - 1987 Dec 1|
ASJC Scopus subject areas
- Physiology (medical)