NEUROHYPOPHYSEAL VASOPRESSIN AND OXYTOCIN AS INFLUENCED BY (6R)-5,6,7,8-TETRAHYDRO-ALPHA-BIOPTERIN IN EUHYDRATED AND DEHYDRATED RATS

Experiments were performed to test a possible role of (6R)-5,6,7,8-tetrahydro-alpha-biopterin dihydrochloride (BH4) in the neurohypophysial vasopressin and oxytocin content in euhydrated and dehydrated rats. Chronic treatment with BH4, administered to not dehydrated animals, was followed by a significant decrease of neurohypophysial vasopressin, but not of neurohypophysial oxytocin. In dehydrated animals the neurohypophysial vasopressin content decreased progressively; this process was not affected significantly by BH4. In rats dehydrated and treated simultaneously with BH4 the decrease of neurohypophysial oxytocin content was distinctly less marked.