• Seasonal variation of the vitamin A2-based visual pigment in the retina of adult bullfrog,Rana catesbeiana
Original Research Article
• Vision Research, Volume 23, Issue 2, 1983, Pages 199-204
• Momoyo Makino, Kuzuo Nagai, Tatsuo Suzuki
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Abstract
Visual pigment composition was determined by HPLC analysis over a one-year period in the adult bullfrog (Rana catesbeiana). In Japan, the vitamin A2-based pigment was only 5% of the total visual pigment from the middle of July to October. The vitamin A2-based pigment increased in November and reached a maximum of 32–36% between January and June. This seasonal variation may relate to the average of outdoor temperature rather than the daylight hours. The amount of vitamin A2-based pigment began to increase when the average temperature became lower than 20°C and it decreased rapidly as the average temperature was higher than 20°C.