Glutamate exocrine dynamics augmented by plasma glutamine and the distribution of amino acid transporters of the rat pancreas.
The nutritional and physiological roles of amino acid (AA)s have been investigated for individual organs. In the current study, we focused on the dynamics of glutamate and transport systems in the pancreas. We employed original procedures to obtain rat pancreatic juice (PJ) subjected to intravenous administration of alanyl-glutamine (AG) for AA analysis. The pancreatic expressions of the transporters were evaluated by immunohistochemistry. We found that glutamate was secreted into the PJ in the basal state. The intravenous administration of AG increased the concentration and total amount of glutamate excreted into the PJ. In terms of the transport systems, L-type AA transporter (LAT1) was identified exclusively in the islet cells. Glutamate transporter 1 (GLT1), glutamate-aspartate transporter (GLAST), vesicular glutamate transporter 1 (VGUT1) and cystine/glutamic acid transporter (xCT) were found in the islet cells. xCT was identified in the duct cells as well, but was not accompanied by the expression of 4F2 heavy chain (4F2hc) staining in the islets and the acinar cells, similar to neutral AA transporter (ASCT2) or b0,+-type AA transporter 1(BAT1). Excitatory AA transporter (EAAC) was identified only in the acinar cells. Glutamate was exclusively found in the acinar cells. We revealed the novel dynamics of glutamate in the rat PJ. The glutamate secretion into the PJ was augmented by plasma glutamine, indicating the de novo metabolisms of glutamate, together with the local expression of the related transporters.
Fukushima
D
D
Advanced Surgical Science and Technology Division, Department of Surgery, Graduate School of Medicine, University of Tohoku, Sendai, Japan.
Doi
H
H
Fukushima
K
K
Katsura
K
K
Ogawa
N
N
Sekiguchi
S
S
Fujimori
K
K
Sato
A
A
Satomi
S
S
Ishida
K
K
Fukushima
K
K
D027322:Amino Acid Transport System X-AG / Q000378:metabolism*; D027182:Amino Acid Transport System y+ / Q000378:metabolism; D026905:Amino Acid Transport Systems / Q000378:metabolism*; D026922:Amino Acid Transport Systems, Acidic; D000818:Animals; D004151:Dipeptides / Q000008:administration & dosage / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism*; D005973:Glutamine / Q000097:blood*; D007515:Islets of Langerhans / Q000378:metabolism; D027283:Large Neutral Amino Acid-Transporter 1 / Q000378:metabolism; D008297:Male; D010179:Pancreas / Q000378:metabolism*; D010189:Pancreatic Juice / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D027322:Amino Acid Transport System X-AG; D027182:Amino Acid Transport System y+; D026905:Amino Acid Transport Systems; D026922:Amino Acid Transport Systems, Acidic; D004151:Dipeptides; D018698:Glutamic Acid; D005973:Glutamine; D027283:Large Neutral Amino Acid-Transporter 1; C054122:alanylglutamine; C000723960:Slc7a11 protein, rat