The effect of hypothyroidism, induced by 6-n-propyl-2-thiouracil administration to rats, on the retinoylation reaction was investigated in rat-testes mitochondria. In hypothyroid mitochondria, compared to euthyroid controls, we found an increase of the all-trans-retinoic acid (RA) bound to mitochondrial proteins by an acylation process (34.2 pmoles RA/mg protein/360 min and 22.2 pmoles RA/mg protein/360 min). This increase, which was time- and temperature-dependent, was accompanied by a strong reduction in the cardiolipin (CL) amount in the mitochondrial membranes of hypothyroid (2.6%) as compared to euthyroid rats (4.5%). Conversely, a decreased retinoylation reaction was observed when CL liposomes were added to mitochondria or mitoplasts from both euthyroid and hypothyroid rats, confi rming a role of CL in the retinoylation process. The ATP level, which was reduced in hypothyroid mitochondria (27.3 pmoles ATP/mg protein versus 67.1 pmoles ATP/mg protein of euthyroid animals), was surprisingly increased in mitochondria by the retinoylation reaction in the presence of 100 nM RA (481.5 pmoles ATP/mg protein of hypothyroid rats versus 84.7 pmoles ATP/mg protein of euthyroid rats).
Effect of cardiolipin on retinoylation reaction in testes mitochondria from hypothyroid rats
LAURIA, GRAZIANTONIO;
2010-01-01
Abstract
The effect of hypothyroidism, induced by 6-n-propyl-2-thiouracil administration to rats, on the retinoylation reaction was investigated in rat-testes mitochondria. In hypothyroid mitochondria, compared to euthyroid controls, we found an increase of the all-trans-retinoic acid (RA) bound to mitochondrial proteins by an acylation process (34.2 pmoles RA/mg protein/360 min and 22.2 pmoles RA/mg protein/360 min). This increase, which was time- and temperature-dependent, was accompanied by a strong reduction in the cardiolipin (CL) amount in the mitochondrial membranes of hypothyroid (2.6%) as compared to euthyroid rats (4.5%). Conversely, a decreased retinoylation reaction was observed when CL liposomes were added to mitochondria or mitoplasts from both euthyroid and hypothyroid rats, confi rming a role of CL in the retinoylation process. The ATP level, which was reduced in hypothyroid mitochondria (27.3 pmoles ATP/mg protein versus 67.1 pmoles ATP/mg protein of euthyroid animals), was surprisingly increased in mitochondria by the retinoylation reaction in the presence of 100 nM RA (481.5 pmoles ATP/mg protein of hypothyroid rats versus 84.7 pmoles ATP/mg protein of euthyroid rats).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
