Ventromedial hypothalamic somatostatin may affect gastric somatostatin concentration in rats

Changes in the somatostatin-like immunoreactivity (SLI) concentrations in gastric antral mucosa were detected by RIA following microinjections of synthetic somatostatin (SS) or cysteamine (CSH) into the ventromedial nucleus of the hypothalamus (VMH). SLI concentrations in the antral mucosa were increased by 60.8% (p less than 0.001) and 42.3% (p less than 0.05), respectively, one and four hours after microinjection of somatostatin (0.5 microgram/0.5 microliter) into the VMH, and decreased by 32.6% (p less than 0.05) four hours after microinjection of cysteamine (15 microgram/0.5 microliter) into the VMH. Moreover, microinjection of somatostatin (0.5 microgram/0.5 microliter) into the VMH could only elicit an increase of 16.0% (p less than 0.05) in the SLI concentration in the antral mucosa one hour after bilateral subdiaphragmatic vagotomies, but still produced an increase of 120.0% (p less than 0.05) following celiac ganglionectomies. In conclusion, somatostatin (exogenous and endogenous) in the VMH seems to affect the gastric somatostatin levels via the vagal nerves.