“The results were quite surprising,” said Sassone-Corsi, Donald Bren Professor of Biological Chemistry. “No one realized that the liver or skin could be so directly affected by light.”
For example, despite the shutdown of all other body clocks, including the central brain clock, the liver knew what time it was, responded to light changes as day shifted to night and maintained critical functions, such as preparing to digest food at mealtime and converting glucose to energy.
Somehow, the liver’s circadian clock was able to detect light, presumably via signals from other organs. Only when the mice were subjected to constant darkness did the liver’s clock stop functioning.
Source: Body parts respond to day and night independently from brain – Neuroscience News