Release of amino acids, fluorescamine-reactive substances and substance P from the epidermis of the living animal

The present study demonstrates a procedure for extraction and determination of stratum corneum amines in the living animal, A non-leaky well, containi ng 10 mM Tris-HCl buffer, pH 7.0, was constructed on the shaved backs of an esthetized animals. It was found that Ser, Ala, Gly and Pro are mainly rele ased from the stratum corneum of 4-month-old guinea pigs, and in 2-month-ol d rats, Gly, Ser and Arg show the highest degree of release. Much lower ami no acid concentrations were observed in 20-month-old rats. This was also re flected by the high levels of fluorescamine-reactive substances released fr om young rat skin as compared to the old animals, The release of the neurop eptide substance P into the aqueous medium was increased 3.2 times upon hea t stimulus as compared to control skin, Amines and other compounds released from the skin may serve as markers for skin aging or for certain skin diso rders, leading to a new approach for their treatments.