Distribution of orexin/hypocretin in the rat median eminence and pituitary.
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.
Date
Y
Y
Third Department of Internal Medicine, Miyazaki Medical College, Kiyotake, Miyazaki, Japan.
Mondal
M S
MS
Matsukura
S
S
Ueta
Y
Y
Yamashita
H
H
Kaiya
H
H
Kangawa
K
K
Nakazato
M
M
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008473:Median Eminence / Q000378:metabolism*; D009479:Neuropeptides / Q000378:metabolism*; D064446:Orexin Receptors; D000068797:Orexins; D010902:Pituitary Gland / Q000378:metabolism*; D011817:Rabbits; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled; D018013:Receptors, Neuropeptide / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D064446:Orexin Receptors; D000068797:Orexins; D043562:Receptors, G-Protein-Coupled; D018013:Receptors, Neuropeptide