Fat storage is partially dependent on vagal activity and insulin secretion of hypothalamic obese rat.
Hypothalamic MSG-obese rats show hyperinsulinemia and tissue insulin resistance, and they display intense parasympathetic activity. Current analysis investigates whether early subdiaphragmatic vagotomy prevents tissue insulin sensitivity impairment in adult obese MSG-rats. Hypothalamic obesity was induced by MSG (4 mg/g BW), daily, from birth up to 5 days. Control animals receiving saline solution. On the 30th day rats underwent bilateral subdiaphragmatic vagotomy or sham surgery. An intravenous glucose tolerance test (i.v.GTT) was performed when rats turned 90 days old. Total white fat tissue (WAT) from rat carcass was extracted and isolated; the interscapular brown fat tissue (IBAT) was weighed. Rather than blocking obesity, vagotomy reduced WAT and IBAT in MSG-obese rats when the latter were compared to sham MSG-rats. High blood fasting insulin and normal glucose levels were also observed in MSG-obese rats. Although glucose intolerance, high insulin secretion, and significant insulin resistance were recorded, vagotomy improved fasting insulinemia, glucose tolerance and insulin tissue sensitivity in MSG-obese rats. Results suggest that increased fat accumulation is caused, at least in part, by high blood insulin concentration, and enhanced parasympathetic activity on MSG-obese rats.
Balbo
Sandra Lucinei
SL
Laboratory of Secretion Cell Biology, Department of Cell Biology and Genetics, State University of Maringá, Avenida Colombo 5790, Maringa, PR, 87020-900, Brazil.
Grassiolli
Sabrina
S
Ribeiro
Rosane Aparecida
RA
Bonfleur
Maria Lúcia
ML
Gravena
Clarice
C
Brito
Marcia do Nascimento
Mdo N
Andreazzi
Ana Eliza
AE
Mathias
Paulo Cezar de Freitas
PC
Torrezan
Rosana
R
D000273:Adipose Tissue / Q000378:metabolism*; D050154:Adiposity / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D018149:Glucose Intolerance / Q000209:etiology; D005951:Glucose Tolerance Test; D048788:Growth and Development / Q000187:drug effects; D007027:Hypothalamic Diseases / Q000139:chemically induced / Q000378:metabolism* / Q000503:physiopathology; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance; D000078790:Insulin Secretion; D008297:Male; D009765:Obesity / Q000139:chemically induced / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar; D012970:Sodium Glutamate; D014628:Vagotomy; D014630:Vagus Nerve / Q000503:physiopathology*
D007328:Insulin; D012970:Sodium Glutamate