MEASUREMENT OF NITRIC-OXIDE SYNTHASE AND ITS MESSENGER-RNA IN GENETICALLY-OBESE (OB OB) MICE/

Recent studies have suggested a role for nitric oxide (NO) in the regu lation of food intake. The obese (ob/ob) mouse is a genetic model of o besity. Previously, it has been demonstrated that ob/ob mice show a ma rked weight reduction when treated with a nitric oxide synthase inhibi tor. In the studies reported here, we demonstrate increased levels of nitric oxide synthase (NOS) and its mRNA in the hypothalamus of geneti cally obese (ob/ob) mice compared to their lean littermate controls (o b/c). NOS levels were 0.016 +/- 0.001 nmol/mg/min in ob/ob compared to 0.009 +/- 0.001 in ob/c (p < 0.01) and NOS mRNA was 32.0 +/- 5.0 pg N OS mRNA/mg total RNA in ob/ob compared to 12.4 +/- 4.0 in ob/c (p < 0. 05). These studies further support the possibility of a role for nitri c oxide in the regulation of food intake.