title: Expression of arachidonate 12-lipoxygenase in rat tissues: a possible role in glucagon secretion.
abstract: There are three isoforms of arachidonate 12-lipoxygenase in mammals: platelet, leukocyte, and epidermal types. We found in this study that the leukocyte-type enzyme was present in rat pineal gland, lung, spleen, aorta, adrenal gland, spinal cord, and pancreas, as assessed by RT-PCR. Immunohistochemical analysis showed that the enzyme was localized in macrophages in lung and spleen, alpha-cells of pancreatic islet, zona glomerulosa cells of adrenal cortex, and neuronal cells of spinal cord and superior cervical ganglion. The presence of the 12-lipoxygenase in pancreatic alpha-cells was confirmed by glucagon staining in a consecutive section. We overexpressed the leukocyte-type 12-lipoxygenase cDNA in a glucagon-secreting alphaTC clone 6 cell line that had been established from a transgenic mouse. Glucagon secretion was stimulated by approximately twofold in the 12-lipoxygenase-expressing cells compared to the mock-transfected and original cells. The results suggest that the 12-lipoxygenase of the leukocyte type augments glucagon secretion from pancreatic islets.
authors.affiliation: Department of Pharmacology, Kanazawa University School of Medicine, Kanazawa, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kawajiri
authors.forename: D
authors.initials: D
authors.lastname: Zhuang
authors.forename: N
authors.initials: N
authors.lastname: Qiao
authors.forename: T
authors.initials: T
authors.lastname: Yoshimoto
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: S
authors.initials: S
authors.lastname: Iseki
authors.forename: K
authors.initials: K
authors.lastname: Hamaguchi
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D001092:Arachidonate 12-Lipoxygenase / Q000276:immunology / Q000378:metabolism*; D015153:Blotting, Western; D002460:Cell Line; D005934:Glucagon / Q000378:metabolism*; D007150:Immunohistochemistry; D007515:Islets of Langerhans / Q000378:metabolism; D007962:Leukocytes / Q000201:enzymology; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009928:Organ Specificity; D010870:Pineal Gland / Q000201:enzymology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D012333:RNA, Messenger; D005934:Glucagon; D001092:Arachidonate 12-Lipoxygenase