ABSTRACT
The dynamics of cortisol level and Na+/K+-ATPase activity that are associated with the maintenance of cell ion homeostasis was studied in skeletal muscles of juvenile circumpolar fish daubed shanny Leptoclinus maculatus (Fries, 1838), an ecologically significant representative of the ichthyofauna of the Arctic Svalbard Archipelago. It was established that the level of cortisol and Na+/K+-ATPase activity decrease during the development of daubed shanny juveniles from stage L2 pelagic juveniles to stage L5 juveniles, which are mainly demersal. The results obtained suggest that cortisol may be involved in the regulation of the activity of one of the main osmoregulatory factors, Na+/K+-ATPase. This may be important for the growth and adaptation of pelagic juveniles of daubed shanny to the demersal habitat during postembryonic development in the Arctic.
Subject(s)
Adenosine Triphosphatases , Hydrocortisone , Animals , Water-Electrolyte Balance , Adaptation, Physiological , Growth and Development , Sodium-Potassium-Exchanging ATPase/metabolismABSTRACT
The Na+/K+-ATPase (NKA) activity in smolts of pink salmon Oncorhynchus gorbuscha (a salmon species introduced in 1959 into the rivers of the Kola Peninsula) was studied in a ten-day cage experiment with fresh, estuarine, and sea water; the fish were caught during seaward migration in the Indera River of the White Sea basin. The development of tolerance to increased salinity in pink salmon smolts was accompanied by NKA activation. In estuarine water characterized by salinity fluctuations (from fresh to sea water) and in the marine environment (28), the NKA activity in pink salmon smolts was significantly higher than in the individuals kept in the cages installed in fresh water. The hypoosmoregulatory ability of pink salmon fry was registered, these data indicated that smoltification in this fish species took place in early ontogenesis. The changes in NKA activity evidenced the readiness of migrating pink salmon fry for the marine phase of their life cycle.
Subject(s)
Salmon , Sodium-Potassium-Exchanging ATPase , Animals , Estuaries , Fresh Water , Salmon/metabolism , Seawater , Sodium , Sodium-Potassium-Exchanging ATPase/metabolismABSTRACT
The estradiol content of muscles during metamorphosis in the daubed shanny (Leptoclinus maculatus) from different fjords of Spitsbergen Island, Svalbard, have been studied using mass spectrometry. The level of estradiol at the L4 larval stage of development is significantly lower than at the L2 stage. Values of this parameter in adults are significantly higher than in post-larvae (stage L5). Variations in the estradiol level during metamorphosis can be associated with the growth stimulation and regulation of the process.
Subject(s)
Estradiol/metabolism , Metamorphosis, Biological , Perciformes/metabolism , Animals , Ecosystem , Perciformes/growth & developmentABSTRACT
Activation of lysosomal degradation process in nervous tissue may be neuroprotective. One of the factors that may influence on expression of lysosomal proteinases is the sex hormone, estradiol (E2). In this regard the expression of lysosomal proteinases after intracerebral injection of beta-amyloid peptide (Aß) was investigated as well as the neuroprotective effect of E2 in Aß-induced neurodegeneration. Intracerebral injection of Aß was shown to cause the significant increase in expression of cathepsin D in rat hippocampus and cerebral cortex. On the background of Aß intoxication, E2 treatment resulted in further increase in cathepsin D gene expression in hippocampus region and in its lowering to the control level in cerebral cortex. It was demonstrated for the first time that neuroprotective effect of E2 may be mediated by cathepsin D up-regulation.
Subject(s)
Alzheimer Disease/metabolism , Amyloid beta-Peptides/toxicity , Estradiol/pharmacology , Lysosomes/drug effects , Lysosomes/enzymology , Neuroprotective Agents/pharmacology , Peptide Fragments/toxicity , Peptide Hydrolases/metabolism , Alzheimer Disease/chemically induced , Alzheimer Disease/pathology , Animals , Female , Gene Expression Regulation, Enzymologic/drug effects , Lysosomes/metabolism , Male , Rats , Rats, WistarABSTRACT
On the basis of experimental series with murine models there was obtained the evidence on calcium-dependent protease activity changes in rat brain at induced neurodegeneration. The properties of the proteolytic and regulatory components of calpain system under the effect of neurotoxic stimuli--amyloid beta-peptide or glutamate--were characterized; the basic endogenous regulatory mechanisms of calcium-dependent proteolysis modulation were determined as well. Neuroprotective properties of exogenous calpain regulators differing in the mechanisms of action (sex steroids, calcium regulators) were tested on studied neurodegeneration models.
Subject(s)
Calpain/biosynthesis , Gonadal Steroid Hormones/metabolism , Nerve Degeneration/metabolism , Amyloid beta-Peptides/administration & dosage , Animals , Brain Mapping , Calcium/metabolism , Calpain/metabolism , Glutamic Acid/administration & dosage , Humans , Models, Animal , Nerve Degeneration/pathology , RatsABSTRACT
Experimental evidences of calcium-dependent proteolysis dysregulation in brain of murine model of Alzheimer disease were obtained. Experimental treatment consisted in intra-hippocampal injection of amyloid beta-peptide (AP1-40) promoted activation of main calpain forms in murine brain along with decrease incontent of natural calpain inhibitor, calpastatin. As a result of prognostic experiment on the correction of neurodegeneration induced in murine the neuroprotective properties of steroid hormone estradiol were confirmed and one of the possible protective action mechanisms was suggested. Obtained results allow considering both biochemical modifications in protein facilities of pathology-affected brain and the mechanisms of neurodegeneration and neuroprotection.
Subject(s)
Alzheimer Disease/drug therapy , Calcium-Binding Proteins/biosynthesis , Calpain/biosynthesis , Nerve Degeneration/drug therapy , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Amyloid beta-Peptides/toxicity , Animals , Calcium/metabolism , Estradiol/metabolism , Estradiol/therapeutic use , Gene Expression Regulation/drug effects , Hippocampus/metabolism , Nerve Degeneration/chemically induced , Nerve Degeneration/pathology , Neuroprotective Agents/administration & dosage , Peptide Fragments/toxicity , Proteolysis/drug effects , RatsABSTRACT
Ageing, melatonin, epithalon (tetrapeptide Ala-Glu-Asp-Gly) and different light conditions effects on protein content and cathepsins B and D activities in rat liver and kidneys lysosomal fractions were studied. Ageing leads to decrease of cathepsins activity in rat liver lysosomal fractions. Constant light and darkness conditions result in earlier age decline of cathepsins activity. Absence of day and night succession in comparison with alternating light conditions causes decline of both general and specific cathepsin D activity. Melatonin and epithalon administration resulted in decrease of cathepsin D activity in liver only under control interchangeable light conditions. Cathepsin B activity in liver and kidneys lysosomal fractions declined in all experimental light conditions. Cathepsins activity decrease under the influence of epiphysial factors is evidently connected with their inhibitory effect on protein and general metabolism.
