Related Experiment Video
Updated: May 19, 2026

Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures
Published on: November 11, 2016
The circadian output signals from the suprachiasmatic nuclei
Jia-Da Li1, Wang-Ping Hu2, Qun-Yong Zhou3
1The State Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan, PR China.
Abstract:
The suprachiasmatic nuclei (SCN) of the anterior hypothalamus comprise a self-sustained biological clock generating an endogenous ∼24-h circadian rhythm, driving many overt daily rhythms in the body. An important remaining question is how the SCN neurons communicate with their efferent targets to control the daily oscillations in behavior and physiology. In this chapter, we summarize several signaling factors that may serve as such SCN output factors. Whereas vasopressin may be involved in the regulation of circadian hormone rhythms, SCN-derived prokineticin 2 (PK2), TGF-α, and cardiotrophin-like cytokine (CLC) may serve as output factors for other circadian rhythms, including locomotor activity, body temperature, and energy metabolism. The circadian rhythm in firing activity of SCN neurons is also likely to be a critical output signaling mechanism. The likely involvement of these output factors in the generation of the circadian rhythm in SCN neuronal firing activity is also discussed.
More Related Videos
Related Concept Videos
Circadian Rhythms and Gene Regulation
Circadian Rhythms and Gene Regulation
Diencephalon: Hypothalamus and Coordination
The hypothalamus interacts with other brain regions, including the pituitary gland, through a direct physical connection called the hypothalamic-pituitary axis. The hypothalamus receives somatic and visceral inputs and...
Biological Clocks and Seasonal Responses
The Pineal Gland
The primary secretion of the pineal gland is the hormone melatonin, derived from serotonin. The concentration of melatonin in the...
Diencephalon: Thalamus and Information Relay

