Induction of interleukin-1 beta mRNA and enkephalin mRNA in the rat adrenal gland by lipopolysaccharides studied by in situ hybridization histochemistry.
Interleukin-1 is a macrophage-derived cytokine, which can also be synthesized in other cell types. It has been shown to exert several activities in the nervous and endocrine system, including a potent activating effect on the hypothalamo-pituitary-adrenal axis. High levels of interleukin-1 have previously been found in the adrenal gland. The effect of bacterial lipopolysaccharides (2.0 mg/kg) on interleukin-1 beta mRNA was studied in the rat adrenal gland by in situ hybridization histochemistry using a synthetic oligonucleotide probe. A transient induction was observed, with the strongest hybridization signal seen after 1.5 h and subsequent decrease to near basal levels at 3 h. Similarly, the effect of lipopolysaccharides on preproenkephalin A mRNA expression in the adrenal gland was analyzed. Preproenkephalin A is a precursor for methionine-enkephalin, a neuropeptide known to be produced in the chromaffin cells, and also known to affect immunological functions. A low level of preproenkephalin A mRNA was seen in the adrenal medulla in animals injected with saline and 0.5 h after lipopolysaccharide administration. A small, but distinct increase in hybridization signal appeared at 1.5 h and a marked increased was observed at 3 h after administration of lipopolysaccharides. In addition to the different kinetics of expression after LPS administration, the two mRNA species showed a somewhat different morphological distribution in that IL-1 beta mRNA could be seen in both adrenal medulla and cortex, whereas preproenkephalin A expression was confined to the adrenal medulla.
Department of Clinical Neuroscience, Karolinska Institute, Novum, KFC, Huddinge, Sweden.
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Schultzberg
D000311:Adrenal Glands / Q000378:metabolism*; D000818:Animals; D001345:Autoradiography; D015152:Blotting, Northern; D004745:Enkephalins / Q000235:genetics*; D017403:In Situ Hybridization; D007375:Interleukin-1 / Q000235:genetics*; D008070:Lipopolysaccharides / Q000378:metabolism*; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013154:Spleen / Q000502:physiology
D004745:Enkephalins; D007375:Interleukin-1; D008070:Lipopolysaccharides; D012333:RNA, Messenger