D-Alanine in the islets of Langerhans of rat pancreas.
Relatively high levels of D-alanine (D-Ala), an endogenous D-amino acid, have been found in the endocrine systems of several animals, especially in the anterior pituitary; however, its functional importance remains largely unknown. We observed D-Ala in islets of Langerhans isolated from rat pancreas in significantly higher levels than in the anterior/intermediate pituitary; specifically, 180±60 fmol D-Ala per islet (300±100 nmol/gislet), and 10±2.5 nmol/g of wet tissue in pituitary. Additionally, 12±5% of the free Ala in the islets was in the d form, almost an order of magnitude higher than the percentage of D-Ala found in the pituitary. Surprisingly, glucose stimulation of the islets resulted in D-Ala release of 0.6±0.5 fmol per islet. As D-Ala is stored in islets and released in response to changes in extracellular glucose, D-Ala may have a hormonal role.
Department of Chemistry and Beckman Institute, University of Illinois at Urbana-Champaign, IL 61801, USA.
Nobutoshi
N
Ota
Department of Chemistry and Beckman Institute, University of Illinois at Urbana-Champaign, IL 61801, USA.
Stanislav S
SS
Rubakhin
Department of Chemistry and Beckman Institute, University of Illinois at Urbana-Champaign, IL 61801, USA. Electronic address: jsweedle@illinois.edu.
Jonathan V
JV
Sweedler
D000409:Alanine / Q000032:analysis / Q000378:metabolism*; D000818:Animals; D007515:Islets of Langerhans / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D010902:Pituitary Gland / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar
D000409:Alanine
Capillary electrophoresis; Chiral separation; Endocrine system; Islets of Langerhans; d-Alanine; d-Amino acid