A GABAB-receptor mechanism is involved in the prolactin release in both male and female rats

Scintigraphy of the reticuloendothelial system (RES) was performed in 19 patients with polycythemia vera (PCV) and in 18 with secondary or relative polycythemia (PS). Bone marrow extension was found in all patients with PCV and in 11 of 18 patients with PS. The patients with PCV had a higher degree of extension than those with PS. Increased pelvic bone marrow activity was found in 16 of 19 PCV patients, but in none with PS. Splenomegaly was found in 9 patients with PCV, and in none with PS. It is concluded that RES scintigraphy in the majority of patients may differentiate between PCV and PS using the parameters pelvic bone marrow activity, bone marrow extension and splenic size.