Androgen manipulation and vasopressin binding in the rat brain and peripheral organs

It is now widely recognized that there is a sexual dimorphism in the development of arginine vasopressin (AVP) immunoreactivity in certain parts of the brain, and that changes in brain A immunoreactivity change with manipulation of androgen status. The aim of this experiment was determine specifically any AVP receptor changes in response to manipulation of androgen levels using selective V¹ antagonist radioligand. Following castration, plasma testosterone levels fell and A immunoreactivity was reduced in the lateral septum and bed nucleus of the stria terminalis. W testosterone supplementation in castrated animals, the immunoreactivity in these regions was restored to a higher degree than in sham-operated animals. Central and peripheral V₁ AVP receptor binding determined using the selective AVP V₁ antagonist radioligand [¹²⁵I](d(CH₂)(5),sarcosine⁷)Avp was changed in any of the brain regions studied or in liver or kidney membranes from the three groups. T study demonstrates that there is no change in brain AVP receptor binding despite changes in regional AVP immunoreactivity in the brain, and excludes any confounding interaction with changes oxytocin receptors.