Differential regulation of adrenomedullin gene expression in the fundic and pyloric regions of the rat stomach during acute and chronic starvation.
Adrenomedullin (AM) has been shown to be present in the stomach but the role of gastric AM is obscure. To investigate the effects of starvation on AM in the stomach, we studied the changes in gene expression of preproadrenomedullin (preproAM) and AM receptors by reverse transcription-polymerase chain reaction (RT-PCR), and tissue AM concentrations by radioimmunoassay (RIA) in the fundus and pylorus of the stomach of rats subjected to either acute (1-day) or chronic (4-day) starvation. An up-regulation of preproAM gene expression was observed in the fundus after acute starvation, and in the pylorus after chronic starvation. Immunoreactive AM (ir-AM) levels were increased in both fundus and pylorus after chronic starvation. In addition, marked reductions in the gene expression of fundic calcitonin receptor-like receptor (CRLR) and receptor activity-modifying protein (RAMP) 3 as well as the pyloric CRLR and RAMP2 were observed in the chronically starved rats. The present study suggests that the gene expression of preproadrenomedullin mRNA is differentially regulated by starvation in the different parts of the stomach.
Man
Siu-Yin
SY
Department of Physiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China.
Hwang
Isabel S S
IS
Li
Yuk-Yin
YY
O
Wai-Sum
WS
Sheng
Hwai-Ping
HP
Tang
Fai
F
D000208:Acute Disease; D053607:Adrenomedullin / Q000096:biosynthesis* / Q000235:genetics* / Q000502:physiology; D000818:Animals; D001835:Body Weight / Q000502:physiology; D002850:Chromatography, Gel; D002908:Chronic Disease; D005748:Gastric Fundus / Q000378:metabolism / Q000502:physiology; D005753:Gastric Mucosa / Q000378:metabolism; D005786:Gene Expression Regulation / Q000502:physiology; D007150:Immunohistochemistry; D007700:Kinetics; D008297:Male; D009929:Organ Size / Q000502:physiology; D011708:Pylorus / Q000378:metabolism / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013217:Starvation / Q000235:genetics* / Q000503:physiopathology*; D013270:Stomach / Q000503:physiopathology*
D012333:RNA, Messenger; D053607:Adrenomedullin