Ventral striatal responses to reduced food intake in healthy animals and rats bearing small tumors

Anorexia is frequently observed during cancer and associated with increased morbidity and mortality. Our previous work has shown the presence of transcription factors in the ventral striatum of anorectic tumor-bearing rats. The aim of the present study was, therefore, to assess expression of neuropeptides, neurotransmitter-synthesizing enzymes and receptors in this structure. Morris hepatoma 7777 cells injected subcutaneously in Buffalo rats provoked a 15% reduction in food intake and 10% lower body weight when the tumor represented 1-2% of body mass. Mircorarrays and real-time PCR revealed increased ventral striatal prostaglandin D synthase expression in food-restricted animals compared to anorectic tumor-bearing rats. These findings indicate that reduced ventral striatal prostaglandin D synthesis underlies cancer-associated anorexia.