In vivo effects of glucocorticoid excess on the contents of the rat fetal liver in erythroid progenitors.
Following a laparotomy of the pregnant rat at 12 days of gestation, erythroid cell suspensions prepared from the fetal livers at 14 days contained an increased proportion of progenitor cells forming colonies after 2 or 7 days of culture. When laparotomy was performed at 14 days and the fetal livers were sampled at 16 days, the opposite effects were observed. Injection of 0.25 mg/kg dexamethasone to the 12 days pregnant rat increased the proportion of erythroid progenitors in suspensions from 14 days fetal livers; injection of 10 mg/kg (a long-acting dose) produced the opposite effects. Both the composition of the erythroid cell line and its environment change between 12 and 14 days, and these modifications might explain the inversion of glucocorticoid effects between these two stages.
Billat
C
C
Laboratoire de Physiologie animale, UER des Sciences Exactes et Naturelles, Moulin de la Housse, Reims, France.
Mayeux
P
P
Felix
J M
JM
Jacquot
R
R
D000818:Animals; D003907:Dexamethasone / Q000008:administration & dosage* / Q000494:pharmacology; D004920:Erythropoiesis / Q000187:drug effects*; D005260:Female; D005333:Fetus / Q000187:drug effects*; D007813:Laparotomy / Q000009:adverse effects; D008099:Liver / Q000187:drug effects*; D011247:Pregnancy; D051381:Rats
D003907:Dexamethasone