The amount of mutant vasopressin precursor in the supraoptic and paraventricular nucleus of Brattleboro rats increases with age.

In the homozygous diabetes insipidus (di/di) Brattleboro rat an aberrant vasopressin (VP) precursor is synthesized. An antiserum raised against a 14 amino acid sequence of this mutant precursor (CP-14) stains neurons in the supraoptic (SON) and paraventricular nucleus (PVN). In the present study it was shown that during life (i.e. from 16 days up to 83 weeks postnatally) the number of CP-14 SON cells and their content gradually increases. Only a few CP-14 SON cells are present in young pre-pubertal di/di rats. The staining becomes increasingly more intense after puberty. In contrast, the number of CP-14 PVN cells remains low in the post-pubertal period.