Effects of endogenous and exogenous glucocorticoids on liver differentiation

The effects of maternal bilateral adrenalectomy on day 1 of gestation and b etamethasone treatment on fetal liver development were compared, in terms o f biochemical and morphological parameters. For fetuses 20 days old (E20), absence of maternal glucocorticoids during gestation caused an increase in the number of nuclei in whole livers, and a significantly decrease of both body weight and protein content per nucleus, in comparison with the control group (C). Betamethasone injection on days 15, 16 and 17 of gestation into adrenalectomized pregnant rats (ADX + BET) did not completely prevent thes e effects. The electron microscopic analysis of the ADX fetal liver (E20) showed some hepatocyte lesions such as loss of cytoplasmic organelles, increase in hema topoietic cell number as well as a lower cellular maturation in comparison with the control group. The fetal liver from ADX + BET mothers 20 days afte r gestation displayed a noticeable involution of the hematopoietic componen t in spite of its relatively immature stage. However, there was no signific ant change in the degree of fetal hepatocyte lesions. Therefore, supply of maternal glucocorticoids from the beginning of gestati on is essential for maintenance of the integral structure of the rat fetal hepatic parenchyma, for the correct maturation of the blood strains and for the beginning of involution of the hematopoietic tissue at the end of gest ation.