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The Mechanism of the Calorigenic Action of Thyroid Hormone : Stimulation of Na(+) + K(+)-activated adenosinetriphosphatase activity

In an earlier study, we proposed that thyroid hormone stimulation of energy utilization by the Na(+) pump mediates the calorigenic response. In this study, the effects of triiodothyronine (T(3)) on total oxygen consumption (Q (O(O2))), the ouabain-sensitive oxygen consumption [Q (O(O2))(t)], and NaK...

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Detalles Bibliográficos
Autores principales: Ismail-Beigi, Faramarz, Edelman, Isidore S.
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1971
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2203122/
https://www.ncbi.nlm.nih.gov/pubmed/4252666
Descripción
Sumario:In an earlier study, we proposed that thyroid hormone stimulation of energy utilization by the Na(+) pump mediates the calorigenic response. In this study, the effects of triiodothyronine (T(3)) on total oxygen consumption (Q (O(O2))), the ouabain-sensitive oxygen consumption [Q (O(O2))(t)], and NaK-ATPase in liver, kidney, and cerebrum were measured. In liver, ∼90% of the increase in Q (O(O2)) produced by T(3) in either thyroidectomized or euthyroid rats was attributable to the increase in Q (O(O2))(t). In kidney, the increase in Q (O(O2))(t) accounted for 29% of the increase in Q (O(O2)) in thyroidectomized and 46% of the increase in Q (O(O2)) in euthyroid rats. There was no demonstrable effect of T(3) in euthyroid rats on Q (O(O2)) or Q (O(O2))(t) of cerebral slices. The effects of T(3) on NaK-ATPase activity in homogenates were as follows: In liver +81% from euthyroid rats and +54% from hypothyroid rats. In kidney, +21% from euthyroid rats and +69% from hypothyroid rats. T(3) in euthyroid rats produced no significant changes in NaK-ATPase or Mg-ATPase activity of cerebral homogenates. Liver plasma membrane fractions showed a 69% increase in NaK-ATPase and no significant changes in either Mg-ATPase or 5'-nucleotidase activities after T(3) injection. These results indicate that thyroid hormones stimulate NaK-ATPase activity differentially. This effect may account, at least in part, for the calorigenic effects of these hormones.