title: Effect of nitrate and L-arginine therapy on nitric oxide levels in serum, heart, and aorta of fetal hypothyroid rats.
abstract: Reduced nitric oxide availability and a heterogeneous pattern of nitric oxide synthase activity in some tissues have been reported in hypothyroidism. This study aimed at determining the effects of oral nitrate and L-arginine administration on serum, heart, and aorta nitric oxide metabolite concentrations in fetal hypothyroid rats. In an experimental study, pregnant Wistar rats were administrated tap water or 0.02 % of 6-propyl-2-thiouracil in drinking water during pregnancy and their male pups were followed (n = 8/group). In adult progeny, serum, heart, and aorta nitric oxide metabolite concentrations were measured by the Griess method after 1-week administration of sodium nitrate (500 mg/L) or L-arginine (2 %) in drinking water. Serum thyroid hormone and thyroid-stimulating hormone levels were also measured. Compared to controls, fetal hypothyroid progeny had significantly lower nitric oxide metabolite concentrations in heart (0.32 ± 0.07 vs. 0.90 ± 0.14 nmol/mg protein, p = 0.004) and aorta (2.98±0.56 vs. 6.15±0.74 nmol/mg protein, p = 0.011) tissues. Nitrate therapy restored heart nitric oxide metabolite levels decreased by fetal hypothyroidism, while L-arginine administration further decreased aorta nitric oxide metabolite levels. Sodium nitrate increased and L-arginine decreased serum nitric oxide metabolite levels in both control and fetal hypothyroid animals. In conclusion, nitrate therapy restores decreased heart nitric oxide metabolite levels, whereas L-arginine decreases aorta nitric oxide metabolite levels even further in fetal hypothyroid rats, findings relevant to the cardiovascular consequences of congenital hypothyroidism in adulthood.
authors.affiliation: Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, No. 24, Parvaneh Street, Velenjak, P.O. Box: 19395-4763, Tehran, Iran, Ghasemi@endocrine.ac.ir.
authors.forename: Asghar
authors.initials: A
authors.lastname: Ghasemi
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Mehrazin
authors.forename: Saleh
authors.initials: S
authors.lastname: Zahediasl
mesh_terms: D000818:Animals; D013956:Antithyroid Agents / Q000009:adverse effects; D001011:Aorta / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D001120:Arginine / Q000009:adverse effects*; D003409:Congenital Hypothyroidism / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D005260:Female; D005333:Fetus / Q000378:metabolism* / Q000473:pathology; D006321:Heart / Q000187:drug effects*; D008297:Male; D009566:Nitrates / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism*; D011247:Pregnancy; D011441:Propylthiouracil / Q000009:adverse effects; D051381:Rats; D017208:Rats, Wistar; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
chemical_list: D013956:Antithyroid Agents; D009566:Nitrates; D014284:Triiodothyronine; D009569:Nitric Oxide; D011441:Propylthiouracil; C031618:sodium nitrate; D013972:Thyrotropin; D001120:Arginine; D013974:Thyroxine