Sex difference in Fel d 1 allergen production.
BACKGROUND
Previous experiments have shown that in vivo Fel d 1 production is under hormonal control. It strongly decreased 1 month after castration of male cats and increased after testosterone injection.


OBJECTIVE
These results led us to put forward the hypothesis that Fel d 1 production could be more important in male that in female cats. Five adult male and five adult female cats were studied.


METHODS
On day 0 three separate sites of each cat's trunk were shaved, and a 5.72 cm2 area in each site was washed twice (D0a and D0b) with 5 ml of distilled water. Then a collar was attached to the neck to prevent contamination from saliva. Twenty-four hours later on day 1, all areas were washed again once (D1a). Skin washes and fur extracts from the shaved areas were evaluated for Fel d 1 content. The same procedures (apart from collection of fur) were repeated 5 months later.


RESULTS
The Fel d 1 level was higher in the first skin wash of male cats compared with that of female cats on each separate site of the trunk in both experiments, initially and 5 months later. Results were significant in the first experiment (median Fel d 1 per milliliter: 69.4 and 28.9 mU, respectively, for the combined three sites; p < 0.05). Fel d 1 production over a 24-hour period was higher in male cats, but the difference did not reach statistical significance. Furthermore, correlation between Fel d 1 levels in washes D0a and in fur was highly significant (p < 0.01).


CONCLUSIONS
These results confirm that Fel d 1 originates from skin. Furthermore, they suggest that Fel d 1 production is higher in male than in female cats.
Jalil-Colome
J
J
Département des Maladies Respiratoires, Hôpital Sainte-Marguerite, Marseille, France.
de Andrade
A D
AD
Birnbaum
J
J
Casanova
D
D
Mège
J L
JL
Lanteaume
A
A
Charpin
D
D
Vervloet
D
D
D000485:Allergens / Q000096:biosynthesis*; D000818:Animals; D002415:Cats; D005260:Female; D006023:Glycoproteins / Q000096:biosynthesis*; D006197:Hair / Q000276:immunology; D008297:Male; D012727:Sex Characteristics; D012867:Skin / Q000276:immunology
D000485:Allergens; D006023:Glycoproteins; C059296:Fel d 1 protein, Felis domesticus