title: Immunological identification of vesicular nucleotide transporter in intestinal L cells.
abstract: It is well established that vesicular nucleotide transporter (VNUT) is responsible for vesicular storage of nucleotides such as ATP, and that VNUT-expressing cells can secrete nucleotides upon exocytosis, playing an important role in purinergic chemical transmission. In the present study, we show that VNUT is expressed in intestinal L cells. Immunohistochemical evidence indicated that VNUT is present in glucagon-like peptide 1 (GLP-1) containing cells in rat intestine. VNUT immunoreactivity is not co-localized with GLP-1, a marker for secretory granules, and synaptophysin, a marker for synaptic-like microvesicles (SLMVs). Essentially the same results were obtained for GLUTag clonal L cells. Sucrose density gradient analysis confirmed that VNUT is present the light fraction, unlike secretory granules. These results demonstrate that intestinal L cells express VNUT in either the unidentified organelles at light density other than secretory granules and SLMVs or a subpopulation of SLMVs, and suggest that L cells are purinergic in nature and secrete nucleotides independent of GLP-1 secretion.
authors.affiliation: Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences.
authors.forename: Yuika
authors.initials: Y
authors.lastname: Harada
authors.forename: Miki
authors.initials: M
authors.lastname: Hiasa
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism; D018929:Cell Culture Techniques; D019858:Enteroendocrine Cells / Q000378:metabolism*; D019084:Fluorescent Antibody Technique, Indirect; D052216:Glucagon-Like Peptide 1 / Q000378:metabolism; D007421:Intestine, Small / Q000166:cytology / Q000378:metabolism*; D008297:Male; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D033704:Nucleotide Transport Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D017208:Rats, Wistar; D011983:Receptors, Purinergic / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013572:Synaptic Vesicles / Q000378:metabolism; D016708:Synaptophysin / Q000096:biosynthesis / Q000302:isolation & purification; D050496:Vesicular Glutamate Transport Proteins / Q000096:biosynthesis / Q000302:isolation & purification
chemical_list: D033704:Nucleotide Transport Proteins; D011983:Receptors, Purinergic; C578984:Slc17a9 protein, mouse; C000595299:Slc17a9 protein, rat; D016708:Synaptophysin; C569015:Syp protein, mouse; C569016:Syp protein, rat; D050496:Vesicular Glutamate Transport Proteins; D052216:Glucagon-Like Peptide 1; D000255:Adenosine Triphosphate