Studies on circadian periodicity of plasma 17-hydroxycorticosteroids (17-OHCS) in tropical pulmonary eosinophilia.

Circadian periodicity of plasma 17-hydroxycorticosteroids (17-OHCS) was studied in ten healthy controls and 25 patients with tropical pulmonary eosinophilia (TPE). Subjects were synchronized for 1 week with diurnal activity from 0600 to 2200 hr and nocturnal rest; meals were taken at 0830, 1300, and 2030 hr. No medications were administered. TPE patients were divided into three subgroups of fourteen, seven, and four each according to the hour of the worsening of their symptoms. Blood samples were collected at 8-hr intervals at fixed clock hours for 24 hr, starting at 0800 in all four groups. We noted a marked rhythm in plasma 17-OHCS in controls, with significant amplitude and an acrophase at 1033 hr. Similarly, all TPE patients exhibited a definite rhythm in plasma 17-OHCS with significant amplitude irrespective of the time of worsening of symptoms, suggesting thereby no relationship between worsening of symptoms and the rhythm. Thus the circadian nature and normal concentration of plasma 17-OHCS were observed to be similar in healthy controls and TPE patients.