Effects of photoperiod on gluconeogenic activity and total lipid concentrationin organs of crabs, Neohelice granulata, challenged by salinity changes

摘要

This study assessed the effects of long (LD) or short (SD) days on the conversion of [~(14)C]-glycerol to [~(14)C]-glucose and total lipid concentration in organs of the crabNeohelicegranulata challenged by a change in external salinity. In the 20‰-acclimated crabs, no differ-ence was found in the concentration of total lipids in the muscle, hepatopancreas, gills, orhemolymph between crabs acclimated to SD or LD. In SD crabs, the total lipid levels in theanterior and posterior gills did not decrease during an osmotic challenge. Only in the pos-terior gills did the total lipid levels decrease during acclimation to the 34‰ medium in LDanimals. The total lipid concentration in the hemolymph decreased after 1 d of osmotic stressin SD, and increased in the hepatopancreas. In LD crabs, the lipid contents decreased grad-ually in muscle, and the hepatopancreas on day 3 after transfer to 34%o medium. In 20‰-acclimated crabs, the gluconeogenesis activity in both sets of gills was higher in LD than inSD animals. The gluconeogenesis capacity decreased in both sets of gills on the first day ofosmotic challenge in SD, and in the posterior gills on the third day in LD crabs. These resultssuggest that in organs of N. granulata, photoperiod affects the metabolic adjustments to anosmotic challenge.