Modulation of nitric oxide by leptin in placental tissues from control and diabetic rats

WHITE V; PUSTOVRH C; CAPOBIANCO E; HIGA R; GONZÁLEZ E; JAWERBAUM A

Buenos Aires

Congreso; XII Biennial Meeting of the Society for Free Radical Research International; 2004

Society for Free Radical Research

Nitric oxide (NO) is a vasodilator of the placental vasculature. Leptin is produced in placental tissues where ists receptors are expressed. Diabetes induces alterations in NO and leptin levels. We evaluated in term placental tissues from control and diabetic (D) rats: 1) leptin levels (EEIA) and the expression of leptin and its receptor (immunohistochemistry), 2) nitric oxide synthase (NOS) expression (immunohistochemistry) and 3) the modulation of nitric oxide production by leptin (nitrate/nitrite levels by the Griess reaction). Results: Leptin levels were lower in D (330 pg/g) than in C placenta (481 pg/g). Leptin expression was found reduced in placenta from diabetic rats when related to controls, particularly in the labyrinth zone. Placental leptin receptors are similarly expressed in both control and diabetic rats. In diabetic placenta iNOS expression is increased. Leptin additions (10 mg/ml) stimulate NO production in both C (83%) and D (128%) placenta. Conclusions: leptin is a modulator of NO production in rat placental tissue, thus contributing to the regulation of placental blood flow. The diabetic pathology induces a reduction in leptin levels, and increases iNOS expression, alterations that may be involved in the abnormal transfer of nutrients and oxygen to the developing fetus.