Abstract: | The effect of bombesin administered intravenously or intracerebroventricularly was investigated in 66 male Sprague-Dawley rats. Blood for determinations was sampled by cannulation of right heart auricle before and four times after the administration of bombesin. It was found that bombesin administered intravenously at doses of 0.5 and 5 micrograms/kg caused an elevation of blood plasma TSH. When administered intracerebroventricularly at doses of 0.1 and 1 microgram per animal bombesin did not change blood plasma TSH concentration; administered by the same way at a dose of 1 um per rat it lowered, however, the response of TSH to TRH. |