Hitoshi Okamura

In 1997, Hajime Tei, Yoshiyuki Sakaki, and Hitoshi Okamura discovered the mammalian period gene PER1 in mice and humans. They also discovered PER2, PER3, and the mammalian homolog of the Drosophila gene timeless. They found that Per1 is light-inducible and can phase shift the circadian clock by light. Okamura worked with Jay Dunlap, a chronobiologist specializing in circadian rhythms in Neurospora, to show that mammalian clocks are similar to neurospora clocks in their use of induction to phase shift. This is in contrast to the drosophila clock, which phase shift via protein degradation rather than induction.

Okamura began his study of circadian rhythms in 1982 with the peptide work in the suprachiasmatic nucleus (SCN) using the technique of histochemistry in Yasuhiko Ibata's laboratory in the Kyoto Prefectural University of Medicine. He established quantitative histochemistry of the suprachiasmatic nucleus (SCN) in the 1980s, and together with Shin-Ichi Inouye, established in vitro slice cultures of the SCN in the early 1990s.

Hitoshi Okamura received his undergraduate, medical, and doctorate in science degrees from the Kyoto Prefectural University of Medicine. After training as a pediatrician at the Children's Medical Center of the Okayama National Hospital (1979-1981), he worked on neuroanatomy at the Kyoto Prefectural University of Medicine (1981-1995). He was then a Professor of Brain Sciences at the Kobe University School of Medicine from 1995-2008. Since 2007, he has worked as a Professor of Systems Biology at the Kyoto University Graduate School of Pharmaceutical Sciences. Since 2014, he has worked as the Research Director of the Japan Science Technology Institute, CREST. His work has focused on understanding mammalian circadian rhythms.

Hitoshi Okamura (born December 2, 1952) is a Japanese scientist who specializes in chronobiology. He is currently a Professor of Systems Biology at Kyoto University Graduate School of Pharmaceutical Sciences and the Research Director of the Japan Science Technology Institute, CREST. Okamura's research group cloned mammalian Period genes, visualized clock oscillation at the single cell level in the central clock of the SCN, and proposed a time-signal neuronal pathway to the adrenal gland. He received a Medal of Honor with Purple Ribbon in 2007 for his research and was awarded Aschoff's Ruler for his work on circadian rhythms in rodents. His lab recently revealed the effects of mA mRNA methylation on the circadian clock, neuronal communications in jet lag, and the role of dysregulated clocks in salt-induced hypertension.