Site of action of 2-deoxy-D-glucose mediating gastric secretion in the cat.

1. Site of action of 2-deoxy-D-glucose (2-DG) responsible for its effect on gastric secretion was investigated in cats prepared with polyethylene or nylon cannulae chronically implanted in the antrum.2. The patterns of their basal secretion and secretory response to slow intravenous administration of 60 mg 2-DG/kg body wt. were determined. After being subjected to selective neural lesions the cats were tested again and the secretory response was compared with the control.3. The normal response to 2-DG in the cat is equivalent to that obtained in the dog. Volume, pH, acid concentration and output, chloride concentration and pepsin output attain peak values in 45-60 min.4. After intercollicular transection of the mid-brain no secretory response occurred except for a tendency of acid concentration to increase. Large lesions of several diencephalic structures did not suppress the secretory response. Only those cats with a circumscribed lesion of the lateral area of the medial and posterior hypothalamus were unresponsive to 2-DG. Acid secretion, as in the decerebrate animals, showed a slight tendency to increase after 2-DG. Lesions immediately rostral, medial and dorsal to the territory of the medial forebrain bundle were ineffective in preventing augmentation of secretion. Destruction of structures contributing fibres to the medial forebrain bundle at hypothalamic levels, such as the neocortex, amygdala, fornix, septal and preoptic areas, did not change the secretory response.5. Intrafascicular neurones of the medial forebrain bundle are suggested as the main site of action of 2-DG on gastric secretion.