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• n  a plant sterol that is converted into vitamin D by ultraviolet radiation

• Chemical twin of ergosterol is cholesterol which is involved with the female sex hormone theelin.
• If ergosterol is exposed to certain wave lengths of ultraviolet light for certain periods the potency of this provitamin is increased so powerfully that, for treating rickets .
• From yeast Researchers Marker Oakwood obtained ergosterol, an organic compound related to Vitamin D-producing cholesterol.