title: ATP-consuming processes in hepatocytes of river lamprey Lampetra fluviatilis on the course of prespawning starvation.
abstract: The work was performed to establish which of the major ATP-consuming processes is the most important for surviving of hepatocytes of female lampreys on the course of prespawning starvation. The requirements of protein synthesis and Na(+)-K(+)-ATPase for ATP in the cells were monitored by the changes in mitochondrial membrane potential (MMP) in the presence of corresponding inhibitors from the peak of metabolic depression (January-February) to the time of recovery from it (March-April) and spawning (May). Integrity of lamprey liver cells was estimated by catalytic activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in blood plasma. In January-February, the share of ATP necessary for protein synthesis was 20-22%, whereas before spawning it decreased to 8-11%. Functioning of Na(+)-K(+)-pump required 22% of cellular ATP at the peak of metabolic depression, but 38% and 62% of ATP in March-April and May, respectively. Progression of prespawning period was accompanied by 3.75- and 1.6-fold rise of ALT and AST activities in blood plasma, respectively, whereas de Ritis coefficient decreased from 2.51±0.34 to 0.81±0.08, what indicates severe damage of hepatocyte membranes. Thus, the adaptive strategy of lamprey hepatocytes to develop metabolic depression under conditions of energy limitation is the selective production of proteins necessary for spawning, most probably vitellogenins. As spawning approaches, the maintenance of transmembrane ion gradients, membrane potential and cell volume to prevent premature cell death becomes the priority cell function.
authors.affiliation: Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 Thorez av., Sankt-Petersburg 194223, Russia. Electronic address: nagalak@mail.ru.
authors.forename: Natalia I
authors.initials: NI
authors.lastname: Agalakova
authors.affiliation: Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 Thorez av., Sankt-Petersburg 194223, Russia.
authors.forename: Irina V
authors.initials: IV
authors.lastname: Brailovskaya
authors.affiliation: Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 Thorez av., Sankt-Petersburg 194223, Russia.
authors.forename: Svetlana A
authors.initials: SA
authors.lastname: Konovalova
authors.affiliation: Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 Thorez av., Sankt-Petersburg 194223, Russia.
authors.forename: Sergei M
authors.initials: SM
authors.lastname: Korotkov
authors.affiliation: Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 Thorez av., Sankt-Petersburg 194223, Russia.
authors.forename: Elena A
authors.initials: EA
authors.lastname: Lavrova
authors.affiliation: Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 Thorez av., Sankt-Petersburg 194223, Russia.
authors.forename: Anatolii A
authors.initials: AA
authors.lastname: Nikiforov
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D003373:Coumaric Acids / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D005260:Female; D005943:Gluconeogenesis / Q000187:drug effects; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D007798:Lampreys / Q000378:metabolism* / Q000502:physiology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008930:Mitochondria, Liver / Q000378:metabolism; D010058:Oviposition / Q000502:physiology; D010667:Phenylpyruvic Acids / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D045483:Rivers; D012621:Seasons; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013217:Starvation / Q000378:metabolism
chemical_list: D003373:Coumaric Acids; D010667:Phenylpyruvic Acids; D011500:Protein Synthesis Inhibitors; C007175:alpha-cyano-4-hydroxycinnamate; D000255:Adenosine Triphosphate; D003513:Cycloheximide; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D000254:Sodium-Potassium-Exchanging ATPase; C031606:phenylpyruvic acid
keywords: Aminotransferases; Hepatocytes; Lamprey; Metabolic depression; Mitochondrial membrane potential; Na(+)-K(+)-pump; Prespawning starvation; Protein synthesis