title: Seasonal variation in glucose and neutral amino acid uptake in the estuarine crab Neohelice granulata.
abstract: This study investigates the mechanisms of glucose and amino acid transport in gills and jaw muscle of N. granulata collected from an estuarine natural population. The physicochemical parameters of the estuarine environment and of this crustacean's hemolymph were measured during different seasons of the year. In summer, the lagoon water osmolality increased (5-6 times), and hemolymph osmolality decreased. In fall, water pH increased, whereas hemolymph pH decreased markedly. In all seasons, 2-deoxi glucose (DG) uptake in gills was significantly higher than 3-O methyl-glucose (MG) uptake. Phloretin reduced DG uptake in gills; phloretin and phlorizin did not affect MG uptake in this organ. DG and MG uptake was highest in gills during spring and summer. In jaw muscle, MG uptake in winter and spring was higher than DG uptake. In fall, gill methyl aminoisobutyric acid (MeAIB) uptake increased. In jaw muscle, MeAIB uptake was higher in spring. The observed changes in glucose uptake and in the type of glucose and amino acid transporter used in gills and muscle appear to be strategies used by N. granulata to minimize seasonal oscillations in the environmental parameters of their estuarine habitat.
authors.affiliation: Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, 90050-170, Porto Alegre, RS, Brazil.
authors.forename: Sandra Costa
authors.initials: SC
authors.lastname: Valle
authors.forename: Paula
authors.initials: P
authors.lastname: Eichler
authors.forename: José Eduardo
authors.initials: JE
authors.lastname: Maciel
authors.forename: Gabriel
authors.initials: G
authors.lastname: Machado
authors.forename: Luiz Carlos
authors.initials: LC
authors.lastname: Kucharski
authors.forename: Roselis Silveira Martins
authors.initials: RS
authors.lastname: Da Silva
mesh_terms: D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D003386:Brachyura / Q000737:chemistry / Q000378:metabolism*; D005880:Gills / Q000737:chemistry / Q000378:metabolism; D005947:Glucose / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008406:Masseter Muscle / Q000737:chemistry / Q000378:metabolism; D012621:Seasons; D014867:Water / Q000737:chemistry / Q000502:physiology
chemical_list: D000596:Amino Acids; D014867:Water; D005947:Glucose