Angiotensin I-like immunoreactive substance in pineal gland of normal and Brattleboro rats with hereditary diabetes insipidus.

An angiotensin I-like immunoreactive substance (AI) was evidenced by a radioimmunoassay technique in the rat brain. The concentration of AI was significantly greater in the pineal tissue as compared to the hypothalamic or cerebral cortex tissue (p less than 0.001); its concentration was also higher in the pineal of the homozygous rats with hereditary diabetes insipidus (Brattleboro strain) as compared to the same tissue of the normal rats (p less than 0.001). The possible role of a pineal angiotensin system in the hydrosaline regulation is discussed.