Kalsbeek, A.

thyroxine bedtime morning - thyroxine administration patient bedtime administration hormone circadian rhythm thyroid level circadian serum levothyroxine rhythm signi endocrinology journal metabolism thyroid hormones hypothyroidism study blood administration time morning administration - thyroxine ingestion ingestion thyroid hormone 24- h blood samples tsh levels analysis absorption cosinor analysis sample serum tsh ficant variation effect signi ficant difference t 4 metabolism fi tted curve signi ficant effect difference p-value evening result albumin tsh surge 24- subject value 0700 h curve protein publishing point blackwell change acrophase circadian rhythm parameters 1·0 thyrotropin t 3/rt ratio author pilot study 24- h period 2200 h breakfast women signi ficance level cosinor t 3 levels range surge circadian variation - thyroxine administration compilation immunometric assay night