Influence of angiotensin II on dog pineal serotonin content.

Intravenous infusion of angiotensin II in different concentrations for 2 h induced an increase in the serotonin contents of pineal gland, hypothalamus and brain stem in dogs. The maximal stimulatory effect was obtained with a concentration of 50 ng angiotensin II/kg body wt./min. Results are interpreted with regard to the concept of an intrinsic isorenin-angiotensin system and its implications at the level of brain nervous tissue and accessory glands. Experimental data indicating the possible existence of positive and negative feedback relationships between the brain isorenin-angiotensin system and serotonin metabolism in the pineal gland, are presented.