Distribution of orexin/hypocretin in the rat median eminence and pituitary

• Published in: Brain research. Molecular brain research. Vol. 76; no. 1; pp. 1 - 6
• Main Authors: Date, Yukari, Mondal, Muhtashan S, Matsukura, Shigeru, Ueta, Yoichi, Yamashita, Hiroshi, Kaiya, Hiroyuki, Kangawa, Kenji, Nakazato, Masamitsu
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 10.03.2000; Elsevier
• Subjects: Animals; Biological and medical sciences; Carrier Proteins - metabolism; Fundamental and applied biological sciences. Psychology; Hypocretin; hypocretins; Hypothalamus. Hypophysis. Epiphysis. Urophysis; Immunohistochemistry; In Situ Hybridization; Intracellular Signaling Peptides and Proteins; Male; median eminence; Median Eminence - metabolism; Morphology. Functional localizations; Neuropeptides - metabolism; Orexin; Orexin receptor; Orexin Receptors; Orexins; Pituitary; Pituitary Gland - metabolism; Rabbits; Radioimmunoassay; Rats; Rats, Wistar; Receptors, G-Protein-Coupled; Receptors, Neuropeptide - metabolism; Reverse Transcriptase Polymerase Chain Reaction; Vertebrates: endocrinology; Immunohistochemistry; Orexin receptor; In situ hybridization; Pituitary; Orexin; Hypocretin; Molecular hybridization; Vertebrata; Mammalia; Rat; Rodentia; Distribution; Median eminence; Pituitary gland; Neuropeptide
• ISSN: 0169-328X; 1872-6941
• DOI: 10.1016/S0169-328X(99)00317-4

We determined the distribution of orexin-A and orexin-B (also known as hypocretin-1 and hypocretin-2) and their receptors in the rat median eminence and pituitary using sensitive radioimmunoassays coupled with high-performance liquid chromatography, immunohistochemistry, and in situ hybridization. Orexin-A and -B were present in the median eminence, adenohypophysis, and neurohypophysis. Orexin fibers were abundant in the median eminence, and a few fibers projected to the neurohypophysis. Both the orexin 1- and orexin 2-receptor mRNAs were expressed robustly in the pituitary intermediate lobe, whereas in the anterior lobe, the orexin 1 receptor was more markedly expressed than the orexin 2 receptor. These two receptor mRNAs were also found in the posterior lobe. These findings may implicate orexin's involvement in additional as yet undefined physiological functions in the hypothalamo-hypophyseal tract.