Various types of thyrotropin-releasing hormone receptors in discrete brain regions and the pituitary of the rat.
Receptors for thyrotropin-releasing hormone (TRH) in the rat brain and the pituitary are heterogenous. The receptors were classified into four types according to the dissociation constant (KD). High-affinity receptors (KD less than 3 nM) are present in the pituitary, hypothalamus, amygdala, and limbic forebrain which contains the nucleus accumbens and the septum. Intermediate-affinity receptors (KD, 5-16 nM) are evidently present in the frontal cortex, hippocampus, striatum, thalamus, and the brainstem, but may also be present in other regions. Low-affinity TRH receptors (KD, 50-80 nM) are seen in the limbic forebrain, amygdala, and the hypothalamus. Very-low-affinity receptors (KD, 215 nM) exist in the pituitary. Experiments using DN-1417 (gamma-butyrolactone-gamma-carbonyl-histidyl-prolinamide citrate), a synthetic TRH analogue with a more potent central activity, indicated the presence of TRH receptors having a high affinity to DN-1417 at least in the limbic forebrain but not in the pituitary. This type of receptor is not labeled by [3H](3-methyl-histidine2)-TRH. Density of the TRH receptor is the highest in the pituitary and next highest in the amygdala.
Funatsu
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K
Teshima
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Inanaga
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K
D000679:Amygdala / Q000032:analysis; D000818:Animals; D001923:Brain Chemistry; D001933:Brain Stem / Q000032:analysis; D002540:Cerebral Cortex / Q000032:analysis; D003342:Corpus Striatum / Q000032:analysis; D006624:Hippocampus / Q000032:analysis; D008032:Limbic System / Q000032:analysis; D008297:Male; D010902:Pituitary Gland / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000032:analysis*; D018025:Receptors, Thyrotropin-Releasing Hormone; D013788:Thalamus / Q000032:analysis; D013973:Thyrotropin-Releasing Hormone / Q000378:metabolism
D011956:Receptors, Cell Surface; D018025:Receptors, Thyrotropin-Releasing Hormone; D013973:Thyrotropin-Releasing Hormone