Monoclonal antibodies against a dopamine-releasing protein (DARP) arrest fetal development, decrease brain catecholamines, and increase adrenal weight of neonatal rats.

Monoclonal antibodies (MAb) were produced against a partially purified dopamine-releasing protein (DARP) to examine the feasible physiological role of this factor during the development of the rat. These IgM isotype MAbs, and not other IgM antibodies (controls), induced a remarkable increase in fetal resorption and stillbirth rate and impaired the developmental increase of catecholamine concentration in the corpus striatum and hypothalamus of newborn rats. Neonatal injections of the anti-DARP MAb (a single injection of 200 mug, 24 h after birth or 40 mug on alternate days during the first 10 days) decreased the dopamine (DA) concentration of the corpus striatum by 30% on Day 10 and 15% on Day 25 and drastically impaired (by 43% on Day 25) the developmental increase in hypothalamic DA.