title: Hexadecane-induced hyperkeratinization of guinea pig skin. IV. A comparison of free amino acid levels in normal and hyperkeratotic epidermis.
abstract: Hyperkeratotic epidermis, produced by the topical application of n-hexadecane, contained only one-third of the normal level of water-soluble, dialyzable nitrogenous materials. This loss in water-soluble nitrogen was in part accounted for by reductions in the concentration of the nutritionally non-essential amino acids, urea, and ammonia to as little as one-third of the normal levels. The concentrations of the nutritionally essential amino acids remained essentially unchanged. With minor exceptions the concentrations of free amino acids in the cornified and non-cornified portions of hyperkeratotic epidermis were similar. The data presented indicated that the reductions in the levels of tissue free amino acids in hyperkeratotic epidermis were related to changes in the rate of metabolism of these substances within the epidermis rather than to a reduced level of tissue proteolysis or to a reduction in the rate of transfer of these metabolites from the blood stream to the epidermis.
authors.forename: J D
authors.initials: JD
authors.lastname: Rossmiller
authors.forename: W G
authors.initials: WG
authors.lastname: Hoekstra
mesh_terms: D000473:Alkanes / Q000008:administration & dosage / Q000494:pharmacology*; D000596:Amino Acids / Q000378:metabolism*; D000641:Ammonia / Q000378:metabolism; D000818:Animals; D004817:Epidermis / Q000187:drug effects* / Q000378:metabolism; D006168:Guinea Pigs; D007642:Keratosis / Q000139:chemically induced*; D008297:Male; D009584:Nitrogen / Q000378:metabolism; D014508:Urea / Q000378:metabolism
chemical_list: D000473:Alkanes; D000596:Amino Acids; D000641:Ammonia; D014508:Urea; C007932:n-hexadecane; D009584:Nitrogen