[Identification of macrophage migration inhibitory factor (MIF) in rat gastrointestinal tract and its role in rat stomach].
Macrophage migration inhibitory factor (MIF) is the first discovered lymphokine. It was originally identified by its ability to prevent the migration of macrophages out of capillary tubes. Since then, the expression of MIF activities has been found at a variety of inflammatory loci, suggesting its role in regulating the function of macrophages in host defence. More recent reports showed that MIF may have functions besides in the immune system. For instance, MIF mRNA and protein are expressed in anterior pituitary cells, brain, embryonic eye lens and differentiating epidermal cells, suggesting its pivotal role in the regulation of neuroendocrine system, cell growth and differentiation. The aim of this study was to examine the presence and localization of MIF mRNA and its product in the gastrointestinal tract of adult rats. For studying the expression of MIF mRNA and protein, Northern blot analysis and immunoblotting were carried out. For examination of cellular localization of MIF in detail, immunohistochemical studies were performed with the use of rabbit polyclonal antibody directed against recombinant rat MIF. MIF mRNA and protein were strongly expressed in the rat gastric mucosa and to a lesser extent in the esophagus, small intestine and colon by Northern blot analysis and immunoblotting. By immunohistochemical study, positive MIF staining was confined within the cytoplasm of parietal cells. Chief cells and surface mucous cells were negative for MIF staining. Intraperitoneal injection of rat gastrin I caused a decline of MIF mRNA level. And after 6 hours of injection, the level of MIF mRNA returned to the level before injection. In the present study, we demonstrate for the first time that MIF mRNA and protein are strongly expressed in gastric parietal cells. Its constitutive expression in parietal cells suggests that MIF may play an important role in parietal cell physiology.
Kudo
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Third Department of Internal Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
D000818:Animals; D015152:Blotting, Northern; D004064:Digestive System / Q000737:chemistry*; D005755:Gastrins / Q000494:pharmacology; D015151:Immunoblotting; D007150:Immunohistochemistry; D008263:Macrophage Migration-Inhibitory Factors / Q000032:analysis* / Q000235:genetics / Q000502:physiology*; D008297:Male; D010295:Parietal Cells, Gastric / Q000737:chemistry / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar
D005755:Gastrins; D008263:Macrophage Migration-Inhibitory Factors; D012333:RNA, Messenger; C036227:gastrin I