title: Regional brain variations of tryptophan, monoamines, monoamine oxidase activity, plasma free and total tryptophan during the estrous cycle of the rat.
abstract: Normal 4-day cyclic rats were sacrificed at 10 a.m. and 3 p.m. on proestrus or estrus and at 10 a.m. on metestrus. Noradrenaline (NA), dopamine (DA) and tryptophan (T) concentrations varied only slightly. Serotonin (5-HT) concentrations showed characteristic changing patterns in many hypothalamic, limbic and midbrain structures with a decrease during proestrus and an increase during estrus being observed. Monoamine oxidase (MAO) activity changes were often parallel to the 5-HT changes, but were not as great. The marked changes in 5-HT early in proestrus are a further indication of its inhibitory effect on gonadotropin release mechanisms before the 'critical period'.
mesh_terms: D000818:Animals; D001679:Biogenic Amines / Q000378:metabolism*; D001921:Brain / Q000201:enzymology / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism; D003342:Corpus Striatum / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D004971:Estrus; D005260:Female; D007031:Hypothalamus / Q000378:metabolism; D008032:Limbic System / Q000378:metabolism; D008636:Mesencephalon / Q000378:metabolism; D008995:Monoamine Oxidase / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D011247:Pregnancy; D051381:Rats; D012701:Serotonin / Q000378:metabolism; D013378:Substantia Nigra / Q000378:metabolism; D014364:Tryptophan / Q000378:metabolism*
chemical_list: D001679:Biogenic Amines; D012701:Serotonin; D014364:Tryptophan; D008995:Monoamine Oxidase; D004298:Dopamine; D009638:Norepinephrine