Nitric oxide is a highly reactive gas that is produced by many tissues and exerts a series of physiological and pathophysiological effects. We studied the changes of the serum testosterone, thyroxine and thyrotropin levels, thyroid and anterior pituitary weights and thyroid cGMP concentrations in male Wistar strain rats treated with estradiol benzoate (EB) (1 mg/kg, im twice a week) and nonselective NO-synthase inhibitor L-NAME (N-omega-nitro-L-arginine methyl ester) alone and with combination of these substances. We have found that L-NAME in a dose 100 mg/kg/day but not in a dose 50 mg/kg/day increased the serum thyroxine and testosterone levels and in the case of testosterone in a higher dose partially blocked its drop when administered simultaneously with EB. The serum thyrotropin levels significantly fell after L-NAME and EB treatment. The cGMP thyroid levels changed only slightly in groups treated EB and L-NAME alone and were significantly decreased in group treated with combination of these substances. The nitric oxide thus seems to be an important modulator of thyroid and testicular function. The cGMP activation cascade is not probably involved in the nitric oxide induced changes of thyroid function.

• MeSH
• Pituitary Gland, Anterior drug effects   metabolism   MeSH
• Estradiol pharmacology   MeSH
• Cyclic GMP metabolism   MeSH
• Enzyme Inhibitors pharmacology   MeSH
• Rats MeSH
• NG-Nitroarginine Methyl Ester administration & dosage   pharmacology   MeSH
• Rats, Wistar MeSH
• Thyroid Gland drug effects   physiology   MeSH
• Nitric Oxide Synthase antagonists & inhibitors   MeSH
• Testosterone blood   MeSH
• Thyrotropin blood   MeSH
• Thyroxine blood   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Estradiol MeSH
• Cyclic GMP MeSH
• Enzyme Inhibitors MeSH
• NG-Nitroarginine Methyl Ester MeSH
• Nitric Oxide Synthase MeSH
• Testosterone MeSH
• Thyrotropin MeSH
• Thyroxine MeSH