Expressions of the prepro-orexin and orexin type 2 receptor genes in obese rat

• Published in: Peptides (New York, N.Y. : 1980) Vol. 23; no. 9; pp. 1689 - 1696
• Main Authors: Yamamoto, Yukiyo, Ueta, Yoichi, Yamashita, Hiroshi, Asayama, Kohtaro, Shirahata, Akira
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.09.2002
• Subjects: Animals; Body Weight; Carrier Proteins - metabolism; fa/fa; Hyperglycemia - metabolism; Hypocretin; Hypothalamus; In Situ Hybridization; In situ hybridization histochemistry; Insulin - pharmacology; Intracellular Signaling Peptides and Proteins; Male; Neuropeptides - biosynthesis; Neuropeptides - metabolism; Orexin; Orexin Receptors; Orexins; Paraventricular Hypothalamic Nucleus - metabolism; Protein Precursors - biosynthesis; Rats; Rats, Zucker; Receptors, G-Protein-Coupled; Receptors, Neuropeptide - biosynthesis; RNA, Messenger - metabolism; Time Factors; Ventromedial Hypothalamic Nucleus - metabolism; Hypothalamus; In situ hybridization histochemistry; fa/fa; Orexin receptors; Hypocretin; Orexin
• ISSN: 0196-9781; 1873-5169
• DOI: 10.1016/S0196-9781(02)00111-0

We examined the expressions of the prepro-orexin gene in the lateral hypothalamic area (LHA), the genes of the neuropeptide Y ( NPY) and proopiomelanocortin ( POMC) in the arcuate nucleus (ARC), the orexin type 1 receptor ( OX1R) gene in the ventromedial hypothalamic nucleus (VMH) and the orexin type 2 receptor ( OX2R) gene in the paraventricular nucleus (PVN) in 6-, 12- and 18-week-old male lean ( Fa/?) and obese ( fa/fa) Zucker rats, using in situ hybridization histochemistry. The fa/fa rats showed hyperglycemia at 12- and 18-week-old. The prepro-orexin mRNA level in fa/fa rats at 18-week-old and the OX2R mRNA level in fa/fa rats at 12- and 18-week-old were significantly decreased compared to controls. The NPY mRNA levels in fa/fa rats at each time point were significantly increased compared to controls, but the POMC mRNA levels were decreased. Prepro-orexin and OX2R mRNA levels in fa/fa rats pretreated with insulin normalized to the levels found in Fa/? rats. These results suggest that the regulation of prepro-orexin gene expression might be independent of the regulation of the NPY and POMC genes in the ARC in fa/fa rats.