Insulin secretion and acetylcholinesterase activity in monosodium l-glutamate-induced obese mice.
OBJECTIVE
Pancreatic islets isolated from mice treated neonatally with monosodium L-glutamate (MSG) were used to study insulin secretion.


METHODS
Total acetylcholinesterase (AchE) activity of tissue extract was measured as a cholinergic activity marker. Obesity recorded in 90-day-old MSG mice (OM) by Lee index reached 366.40 +/- 1.70, compared to control mice (CM) 324.40 +/- 1.10 (p < 0.0001). Glucose 5.6 mM induced insulin secretion of 36 +/- 5 pg/15 min from islets of CM and 86 +/- 13 from OM (p < 0.001). When glucose was raised to 16.7 mM, islets from OM secreted 1,271 +/- 215 and 1,017 +/- 112 pg/30 min to CM. AchE activity of pancreas from OM was 0.64 +/- 0.02 nmol of substrate hydrolyzed/min/mg of tissue and 0.52 +/- 0.01 to CM (p < 0.0001). Liver of obese animals also presented increase of AchE activity.


RESULTS
These indicate that OM insulin oversecretion in low glucose may be attributed, at least in part, to an enhancement of parasympathetic tonus.
Lucinei Balbo
S
S
Laboratory of Secretion Cell Biology, Department of Cell Biology and Genetics, University of Maringá, Brazil.
Gravena
C
C
Bonfleur
M L
ML
de Freitas Mathias
P C
PC
D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000503:physiopathology*; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008297:Male; D051379:Mice; D009765:Obesity / Q000139:chemically induced* / Q000503:physiopathology*; D010179:Pancreas / Q000201:enzymology; D012970:Sodium Glutamate; D013154:Spleen / Q000201:enzymology
D007328:Insulin; D000110:Acetylcholinesterase; D005947:Glucose; D012970:Sodium Glutamate