Hypothyroidism impairs the circadian rhythmicity of clock genes and proteins involved in gut nutrient absorption in female mice.

Hypothyroidism is a common thyroid dysfunction with a higher prevalence in women. Impairments in the regulation of basal metabolism, small intestine nutrient transporter, dyslipidemia, and disruption in circadian clocks have been associated with the thyroid disorder. This study aimed to evaluate whether hypothyroidism affects the small intestine circadian clock and the daily expression pattern of gut nutrient transporters in female mice.

Hypothyroidism alters the rhythmicity of the central clock, body temperature and metabolism: evidence of Bmal1 transcriptional regulation by T3.

In mammals, the central circadian oscillator is located in the suprachiasmatic nucleus (SCN). Hypothalamus-pituitary-thyroid axis components exhibit circadian oscillation, regulated by both central clock innervation and intrinsic circadian clocks in the anterior pituitary and thyroid glands. Thyroid disorders alter the rhythmicity of peripheral clocks in a tissue-dependent response; however, whether these effects are influenced by alterations in the master clock remains unknown.