title: Effect of the liquorice root derivatives on salt and water balance in a teleost fish, rainbow trout (Oncorhynchus mykiss).
abstract: The effect of liquorice root derivatives (LRDs) glycyrrhizic acid (GL) and glycyrrhetinic acid (18βGA) on salt and water balance and end points of gill ion transport in a freshwater teleost, (rainbow trout) was examined after feeding fish diets containing GL or 18βGA (0, 5, 50 or 500 µg/g diet) for a two week period. Serum cortisol levels and gill 11β-hydroxysteroid dehydrogenase type 2 mRNA abundance decreased in fish fed GL but increased (at select doses) in fish fed 18βGA. At higher doses of GL, gill Na(+)-K(+)-ATPase and H(+)-ATPase activity increased, while cystic fibrosis transmembrane conductance regulator type II mRNA abundance significantly decreased at the lowest dose of GL. End points of gill transcellular ion transport were not significantly altered in fish fed 18βGA, except for a reduction in Na(+)-K(+)-ATPase activity at a 50 µg/g dose. In contrast, high doses of GL and 18βGA increased gill transcript abundance of the tight junction protein claudin-31 (cldn-31). Other end points of gill paracellular transport differed in fishes fed LRDs. Tricellulin mRNA abundance was increased by high dose GL and decreased by high dose 18βGA, and cldn-23a and cldn-27b mRNA abundance significantly decreased in response to GL irrespective of dose. Despite the above observations, systemic end points of salt and water balance (i.e. serum [Na(+)] and [Cl(-)] as well as muscle moisture) were unaffected by LRDs. Therefore data suggest that LRDs can alter end points of ion transport in fishes but that overall salt and water balance need not be perturbed.
authors.affiliation: Department of Biology, York University, Toronto, Ontario, Canada M3J 1P3. Electronic address: kupo@yorku.ca.
authors.forename: Chun Chih
authors.initials: CC
authors.lastname: Chen
authors.affiliation: Department of Biology, York University, Toronto, Ontario, Canada M3J 1P3.
authors.forename: Dennis
authors.initials: D
authors.lastname: Kolosov
authors.affiliation: Department of Biology, York University, Toronto, Ontario, Canada M3J 1P3.
authors.forename: Scott P
authors.initials: SP
authors.lastname: Kelly
mesh_terms: D000818:Animals; D015870:Gene Expression / Q000187:drug effects; D005880:Gills / Q000187:drug effects / Q000378:metabolism; D006034:Glycyrrhetinic Acid / Q000008:administration & dosage* / Q000737:chemistry; D006035:Glycyrrhiza / Q000737:chemistry; D019695:Glycyrrhizic Acid / Q000008:administration & dosage* / Q000737:chemistry; D017136:Ion Transport / Q000187:drug effects; D017686:Oncorhynchus mykiss; D012333:RNA, Messenger / Q000096:biosynthesis; D000254:Sodium-Potassium-Exchanging ATPase / Q000096:biosynthesis; D014882:Water-Electrolyte Balance / Q000187:drug effects*
chemical_list: D012333:RNA, Messenger; D019695:Glycyrrhizic Acid; D000254:Sodium-Potassium-Exchanging ATPase; D006034:Glycyrrhetinic Acid
keywords: 11β-Hydroxysteroid dehydrogenase type 2; Cortisol; Gill; Glycyrrhetinic acid; Glycyrrhizic acid; Ion transport; Tight junction