Studies on circadian variations of plasma TSH, thyroxine and triiodothyronine in man.

摘要: To evaluate the existence of circadian variations in thyroid hormone and TSH levels, blood was drawn every 20 min for 24 h four 14 one volunteer. Hormones were measured by sensitive radioimmunoassays. TSH: A diurnal rhythmicity could be demonstrated with peaks from 8 p.m. to 2 a.m a nadir 7 a.m. Superimposed on rhythm multiple shortlived fluctuations observed. Thyroxine: Pooled data showed peak values 12 lowest levels 11 3 Again, superimposed all instances. Triiodothyronine: Hormone highest 1 Fluctuations T3 less marked than those T4. Diurnal can most, but not are minor do exceed normal range. Therefore these changes no relevance routine testing hormones.