Related Experiment Video
Updated: Aug 5, 2026

Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures
Published on: November 11, 2016
CLOCK rs1801260 and MTNR1B rs10830963 Polymorphisms Modulate the Association between Cholesterol Levels and Circadian
D G Gubin1,2, S N Kolomeychuk3,4, I M Petrov3
1Tyumen State Medical University, Ministry of Health of the Russian Federation, Tyumen, Russia. dgubin@mail.ru.
None:
Extreme photoperiods in the Arctic (polar day, polar night, and spring equinox) can disrupt circadian rhythms and impact metabolism and health. The study was aimed to assess the association between the phase angle of physical activity relative to received blue light (ψPA-BL) and the lipid profile. The study included 64 participants who underwent seasonal 7-day actigraphy with an RGB sensor, as well as genotyping for CLOCK rs1801260 and MTNR1B rs10830963 polymorphisms. Multiple regression analysis adjusting for photoperiod, age, and sex showed that ψPA-BL is a predictor of total cholesterol and LDL cholesterol levels only in individuals with the TT/CC genotypes (p < 0.0001). This TT/CC combination exhibited the strongest association with total cholesterol (r = -0.684, explained variance = 47%) and LDL cholesterol (r = -0.623, explained variance = 39%).
Related Concept Videos
Circadian Rhythms and Gene Regulation
Chronopharmacokinetics: Circadian Rhythms and Influence on Drug Response
The time of drug administration is an important factor to consider, as it can influence the toxic dose of a drug. For example, a study conducted by Prins et al. in 1997 examined the effects of the timing of...
Biological Clocks and Seasonal Responses

