[Origin of allergens in the cat]

Danders and animal products have long been recognized as major allergens. One of the most common animals responsible for allergy is cat. Fel d I the major allergen has been detected in fur and a number of authors have claimed that saliva is the principal source of this major allergen and that pelt is contaminated as a result of licking during grooming. We could demonstrate that one of the major sources of Fel d I present on the skin are sebaceous glands and that the production of Fel d I is under hormonal control at least in male cats. Castration decreases significantly the level of Fel d I on the skin and the injection of testosterone reverses the phenomenon. These data lead to continue the work about the regulation of this protein and the knowledge of its biological function.