Resumen de Effect of hypertension on the angiotensin II fibres arriving at the posterior lobe of the hypophysis of the rat. An immunohistochemical study

M.M. Pérez Delgado, Emilia María Carmona Calero, Norberto Marrero Gordillo, H. Pérez Pérez, Agustín Lorenzo Castañeyra Perdomo

• We studied immunohistochemically the posterior lobe of the hypophysis (PL) of 15-week-old spontaneously hypertensive rats (SHR) and of matched normotensive Wi star Kyoto rats (WKY), by using our own polyclonal antibody raised in mice against Angiotensin II (mouse-antiangiotensin II, MAAII). The blood pressure, water intake and volume of the PL were also recorded. The SHR rats were hypertensive, drank more water and showed a clear hypertrophy of their hypophysial PL. Also the PL of the SHR animals showed an increase in the immunoreactivity to the antiangiotensin II antibody in the fibres arriving at the PL, with respect to the PL of WKY rats. This increase is compatible with the hyperactivity of the brain RAS, depletion of vasopressin content in the PL and increase in plasmatic levels of vasopressin described in SHR rats with respect to normotensive animals, as angiotensin II could locally stimulate vasopressin release to plasma from the neurohypophysis.