Aim: In this experimental study, effects of maternal hypervitaminosis A on expression of Transforming Growth Factor Beta^-2 (TGF-&beta2) in fetal heart tissue were investigated by immünohistochemical method.

Material Method: Twenty-seven Wistar female rats were used in this study. These rats were mated and pregnant rats were gavage fed single dose 60 mg/kg body weight of all-trans retinoic acid on 8 day or 12 day of gestation. Conceptus were removed from uterus and they were examined on 15., 18. and 20. day of gestation. Fetal heart tissue were fixed with Boins solution and prepared by immünohistochemically method for ligth microscopic examination.

Results: In this study, expression of TGF-β2 were observed generally at pericardial and endocardial layer of heart tissue. Moreover myocardial cells of control fetuses at 20th day of gestation expressed TGF-β2 protein. Retinoic acid which was adminestered at 8th day of gestation was reduced expression of TGF-b2 but adminestered on 12th day of gestation did not effected of TGF-β 2 expression.

Conclusion: Immunohistochemical expression of TGF β2 was changed depending upon administration time of all-trans retinoic acid in heart tissue. Adminestered all-trans retinoic acid on 8 day of gestation was decreased the expression of TGF-β 2 in fetal heart tissue but adminestered all-trans retinoic acid on 12 day of gestation did not effect of expression of TGF-β