title: Seasonal variation of the vitamin A2-based visual pigment in the retina of adult bullfrog, Rana catesbeiana.
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 degrees C and it decreased rapidly as the average temperature was higher than 20 degrees C.
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D011892:Rana catesbeiana / Q000378:metabolism*; D012168:Retinal Pigments / Q000378:metabolism*; D012172:Retinaldehyde / Q000031:analogs & derivatives / Q000378:metabolism; D012621:Seasons; D013696:Temperature; D014801:Vitamin A / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D012168:Retinal Pigments; C024366:vitamin A2; D014801:Vitamin A; C017184:dehydroretinal; D012172:Retinaldehyde