Transporte de Ca2+ por mitocondrias cardiacas e hepaticas : efeitos de Mg2+, fosfato e estado de oxidação do NAD(P)

AUTOR(ES)
DATA DE PUBLICAÇÃO

1979

RESUMO

Parallel measurements of Ca POT. 2+ uptake, oxygen consumption, endogenous Mg POT. 2+ efflux and swelling in rotenone poisoned rat liver and rat heart mitochondria, showed that heart mitochondria is much more resistant to uncoupling by Ca POT. 2+ in the presence of phosphate than rat liver mitochondria. The extents of Mg POT. 2+ efflux and swelling induced by Ca POT. 2+ accumulation are also much less pronounced in heart mitochondria. Uncoupling and swelling in liver mitochondria seems to be a result of the loss of membrane bound Mg POT 2+ as a consequence of Ca POT. 2+ recycling across the membrane induced by phosphate. Exogenous Mg POT 2+ protects liver mitochondria against the deleterious effects of Ca POT. 2+ by inhibiting a ruthenium red-insensitive Ca POT. 2+ efflux induced by phosphate. Phosphate does not induce recycling of Ca POT. 2+ in heart mitochondria. On the other hand when respiring on NAD-linked substrates or with succinate in the absence of rotenone heart mitochondria behave like liver mitochondria with respect to the alterations caused by Ca POT. 2+ movements. In this case the recycling of Ca POT. 2+ is a consequence of the more oxidized state of mitochondrial Pyridine Nucleotides.

ASSUNTO(S)

calcio mitocondria - membranas fosfatos - oxidação

ACESSO AO ARTIGO

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