title: Anoxia- and hypoxia-induced expression of LDH-A* in the Amazon Oscar, Astronotus crassipinis.
abstract: Adaptation or acclimation to hypoxia occurs via the modulation of physiologically relevant genes, such as erythropoietin, transferrin, vascular endothelial growth factor, phosphofructokinase and lactate dehydrogenase A. In the present study, we have cloned, sequenced and examined the modulation of the LDH-A gene after an Amazonian fish species, Astronotus crassipinis (the Oscar), was exposed to hypoxia and anoxia. In earlier studies, we have discovered that adults of this species are extremely tolerant to hypoxia and anoxia, while the juveniles are less tolerant. Exposure of juveniles to acute hypoxia and anoxia resulted in increased LDH-A gene expression in skeletal and cardiac muscles. When exposed to graded hypoxia juveniles show decreased LDH-A expression. In adults, the levels of LDH-A mRNA did not increase in hypoxic or anoxic conditions. Our results demonstrate that, when given time for acclimation, fish at different life-stages are able to respond differently to survive hypoxic episodes.
authors: Laboratório de Ecofisiologia e Evolução Molecular, Instituto Nacional de Pesquisas da Amazônia, Manaus, AM, Brazil.
authors: Vera Maria Fonseca
authors: VM
authors: Almeida-Val
authors: Alice Reis
authors: AR
authors: Oliveira
authors: Maria
authors: M
authors: de Nazaré Paula da Silva
authors: Monica Stropa
authors: MS
authors: Ferreira-Nozawa
authors: Roziete Mendes
authors: RM
authors: Araújo
authors: Adalberto Luis
authors: AL
authors: Val
authors: Sérgio Ricardo
authors: SR
authors: Nozawa