Yonago Acta medica 1996;38:135-140

The Effect of Inhaled Beclomethasone on the Circadian Changes in Forced Expiration Tests in Normal Subjects

Tadashi lgishi, Katsuhiko Fukuda, Yutaka Hitsuda, Kazuhito Yasuda, Yuji Kawasaki, Yukio Matsumoto and Takao Sasaki

Third Department of Internal Medicine, Faculty of Medicine, Tottori University, Yonago 683, Japan

Circadian rhythms of forced expiration have been detected in normal subjects. But the mechanism remained unclear. This study was designed to clarify the contribution of glucocorticoid to these rhythms. Forced expiration of 8 healthy men were measured at 08:00, 14:00, 20:00 and 02:00 using a dry sealed spirometer. At the same time, serum cortisol level was determined. Moreover, the effects of inhaled beclomethasone at 16:00 and 22:00 on the circadian changes of forced expiration were examined. Each spirometric parameters showed a circadian change with a maximum value at 14:00 and a decreasing tendency thereafter. Serum cortisol level was the highest at 08:00 with a decreasing tendency thereafter. Inhaled beclomethasone at 16:00 and 22:00 inhibited falls in flow at 50% of vital capacity and flow at 25% of vital capacity at night. The fall in serum cortisol level at night may be related, at least, to the peripheral air-way narrowing in the midnight.

key words: beclomethasone; circadian change; cortisol; forced expiration; spirometric parameters

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