Thyroid state and brain monoamine metabolism.
The rates at which rat brain synthesizes catecholamines and serotonin were estimated by measuring the accumulation of DOPA and 5-hydroxytryptophan (5-HTP) 45 min after ip administration of the decarboxylase inhibitor RO4-4602 (800 mg/kg BW). Following thyroparathy-roidectomy, hypothyroid rats showed a decreased accumulation of both precursor amino acids. On the other hand, hyperthyroidism (caused by administering 15 mug T4/100 g BW for 25 days) accelerated the accumulation of catecholamines and serotonin. The accumulation of 5-HTP correlated closely with brain tryptophan concentration in all treatment groups; DOPA accumulation, however, did not similarly correspond to brain tyrosine levels.
D006916:5-Hydroxytryptophan / Q000378:metabolism*; D000818:Animals; D001545:Benserazide / Q000494:pharmacology; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D004295:Dihydroxyphenylalanine / Q000378:metabolism*; D006980:Hyperthyroidism / Q000378:metabolism; D007037:Hypothyroidism / Q000378:metabolism; D008297:Male; D010280:Parathyroid Glands / Q000502:physiology; D051381:Rats; D013961:Thyroid Gland / Q000187:drug effects / Q000502:physiology* / Q000503:physiopathology; D013965:Thyroidectomy; D013974:Thyroxine / Q000494:pharmacology; D014364:Tryptophan / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*
D014443:Tyrosine; D004295:Dihydroxyphenylalanine; D001545:Benserazide; D014364:Tryptophan; D006916:5-Hydroxytryptophan; D013974:Thyroxine