Artificial induction of azurocytes in the meadow vole (Microtus Pennsylvanicus)

Abstract 1. Meadow voles ( Microtus pennsylvanicus ) were manipulated with various biological response modifiers to develop a protocol for artificial induction of azurocytes (AZ). Only progestin hormones, and interferon inducers such as polyinosinc polycytidilic acid or Reovirus-3, initiated AZ maturation. A synthetic progestin, medroxyprogesterone acetate (MPA) was the most effective agent. 2. Following a single injection of 5 mg MPA, AZ appeared in the blood on day 3 or 4. Cells peaked at about 10 9 cells/1 on days 7 through 10. Numbers declined sharply afterwards, suggesting a lifespan for the cell of about 1–2 weeks. 3. Splenectomy of MPA-treated voles had no effect on the number of AZ induced. Attempts at indirect induction through transfer of tissues from MPA-treated voles early in the induction process were unsuccessful. 4. Induction of AZ with MPA was accompanied by severe lymphopaenia. Lymphopaenia was also observed when AZ were induced with polyinosinic polycytidilic acid, but it was not observed during natural pregnancy. Lymphopaenia was not observed in MPA-treated splenectomized voles, despite the induction of large numbers of AZ.