Further evidence of the in vivo role of erythropoietin or companion molecules induced by hypoxia on proliferation and continuing differentiation of BFU-e in PCDC

Abstract

Normal and plethoric bone marrow cells were grown in plasma clot diffusion chambers (PCDC) implanted into the peritoneum of normal mice or mice submitted to 7 her of hypoxia (23,000 ft) daily, on a single day or on 2 consecutive days at different times after implantation of the PCDC's. Daily discontinuous hypoxia (DDH) produced more 6-day bursts than other treatments. Hypoxia on days 1 and 2 after implantation was nearly as effective as DDH on day-6 bursts. Later bouts of hypoxia or a singly hypoxic exposure on day 1 or 2 was less effective. Erythropoietin (Ep) levels were measured by bioassay on both diffusion chamber (DC) contents and serum. Serum Ep levels peaked at 160 mU/ml after a 7-hr hypoxic exposure while the DC content Ep levels were in the nondetectable range (less than 50 mU/ml). The data implies that either higher than normal Ep levels or a companion molecules (s) produced by hypoxia are required for 1–2 days early in the culture period of force an increasing number of BFU-d-e down the erythrocytic pathway and thus increase red cell production at times of need in vivo.

Diffusion chamber colony‐forming unit (cfu‐d): A primitive stem cell

“…Activity produced by antigen-or Schistosomu munsoni-stimulated lymphoid cells [97,98] seems to be a good source of an eosinophilopoietic factor. Erythropoietin, the physiological regulator of in vivo erythropoiesis, also enhances erythroid cell production in DCs [13, 30,36,871. Assessment of conditioned media from neoplastic cell line cultures has revealed that cells with T [24,50] and B cell [49] characteristics elaborate activities which stimulate CFUd.…”