Evaluation of endothelial and inducible nitric oxide synthase genes expression in the heart of broiler chickens with experimental pulmonary hypertension.

1. To clarify the effect of T(3)-induced pulmonary hypertension on endothelial and inducible nitric oxide synthase (eNOS and iNOS) mRNA expression in the ventricles of the heart, semi quantitative reverse transcription-PCR was performed on total RNAs isolated from broiler chicken hearts after feeding supplementary T(3) (15 mg T3/kg) for 6 weeks. NO metabolites (nitrite/nitrate) of serum were measured. 2. The eNOS and iNOS genes were expressed in the right and left ventricles of control and T(3)-treated broilers at 12, 28 and 49 d of age. The relative amount of eNOS mRNA expression in the right and left ventricles did not significantly differ between control and T(3)-treated broilers at any age. 3. The relative amount of iNOS mRNA expression in the right and left ventricles was lower in T(3)-treated broilers than in control broilers at 49 d of age, but not at 12 or 28 d. 4. The amount of NO metabolites was reduced in the serum of T(3)-treated chickens at 49 d of age when compared with the control. 5. It is concluded that eNOS and iNOS genes are normally expressed in the heart of broilers. It is probable that impaired NO synthesis and reduction of iNOS gene expression in the heart ventricles are involved in the pathophysiology of cardiac function in broilers with pulmonary hypertension.