Effects of lipopolysaccharide and glucocorticoids on expression of interleukin-1 beta converting enzyme in the pituitary and brain of mice.

The present study was carried out to determine whether those factors which regulate the expression of IL-1 beta in immune and non-immune tissues are also able to regulate the expression of ICE. In a first experiment, mice were injected with LPS (10 micrograms/mouse, i.p.) and killed before, 1, 3 or 6 h after the injection. Total RNAs were extracted from the spleen, pituitary and brain (hippocampus and hypothalamus) and submitted to RT-PCR to determine the levels of ICE mRNA as compared to beta 2 microglobulin mRNA. ICE mRNAs were more abundant in the spleen and hippocampus than in the pituitary and hypothalamus but they were not significantly altered by LPS treatment. In a second experiment mice were submitted to adrenalectomy or a 15 min restraint stress and injected with saline or LPS (10 micrograms/mouse. sc). They were killed 1-2 h later and total RNA was extracted from the same tissues as in experiment 1. Adrenalectomized mice had significantly higher ICE mRNA levels whereas stressed mice had significantly lower ICE mRNA levels than their respective controls. These results are discussed with respect to the possible regulatory influence of glucocorticoids on the expression of ICE.