Sunlight, season, skin pigmentation, vitamin D, and 25-hydroxyvitamin D: integral components of the vitamin D endocrine system.
Norman
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AW
D044383:Black People; D002762:Cholecalciferol / Q000096:biosynthesis*; D004703:Endocrine System / Q000378:metabolism; D006801:Humans; D018462:Photobiology; D012621:Seasons; D012867:Skin / Q000737:chemistry / Q000378:metabolism*; D012880:Skin Pigmentation; D013472:Sunlight; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism; D044465:White People
D014807:Vitamin D; D002762:Cholecalciferol; C104450:25-hydroxyvitamin D