Color vision depends on thyroid hormone in mice & rats
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https://www.sciencedaily.com/releases/2011/03/110329172251.htm
In the retina of the eye, the cones are the visual cells responsible for colour vision. Most mammals have two spectral cone types containing either of two visual pigments (opsins), one sensitive to shortwave light (UV/blue opsin), the other to middle-to-longwave light (green opsin). Cones express a thyroid hormone receptor.
Its activation by the hormone suppresses the synthesis of UV/blue opsin and activates the production of green opsin.
Until now, the control of opsin production by thyroid hormone was considered a developmental phenomenon.
. The study shows that opsin production in mature cones continues to depend on the thyroid hormone level."Then we wanted to know how long the time window for the hormone effect was, at what point the hormone's influence on opsin production stopped,
To our surprise we did not find such an endpoint, even several weeks after birth there was a hormone effect."
So the team analysed the cones in adult mice and rats that had been rendered hypothyroid for several weeks. In these mice all cones switched to the production of UV/blue opsin and reduced green opsin production. After termination of the treatment, hormone levels returned to normal and the cones reverted to the production of their 'regular' opsin -- one cone type to green opsin, the other to UV/blue opsin.
The researchers conclude that the spectral cone types, which are defined by the opsin they express, are dynamically and reversibly controlled by thyroid hormone throughout life
