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2-Macroglobulin expression in the liver in response to inflammation is mediated by the testis
1 Population Council, Center for Biomedical Research, 1230 York Avenue, New York, New York 10021, USA
2 Department of Zoology, University of Hong Kong, Hong Kong, China
(Requests for offprints should be addressed to C Yan Cheng; Email: Y-Cheng{at}popcbr.rockefeller.edu)
Wing-Yee Luis present address is Department of Zoology, Faculty of Science, University of Hong Kong, Hong Kong, China
Earlier studies have shown that germ cells or germ cell-conditioned media are capable of regulating
2-macroglobulin (
2-MG, a non-specific protease inhibitor) expression by Sertoli cells and hepatocytes cultured in vitro. These results illustrate a possible physiological link between testes and liver regarding
2-MG production. Using a series of surgical procedures including castration, hemicastration, and hepatectomy coupled with Northern blot and immunoblot analyses, we report herein that the surge in
2-MG expression in the liver in response to inflammation is indeed regulated, at least in part, by the testis via testosterone. It was found that hepatectomy induced at least a tenfold increase in the steady-state mRNA and protein production of
2-MG in the liver. However, castration induced a mild but not statistically significant induction of
2-MG in the liver in contrast to sham operation or hemicastration alone, when hemicastration alone could induce liver
2-MG production by almost fourfold. Perhaps most important of all, hepatectomy accompanied by castration significantly reduced the liver
2-MG response to the surgery-induced inflammation compared with hepatectomy alone, illustrating that the removal of the testicles can induce a loss of signal communications between the testis and the liver, rendering a significant loss of the
2-MG response to experimentally induced inflammation in the liver. Interestingly, this lack of response of the liver to surgery-induced inflammation regarding
2-MG production following castration could be restored, at least in part, by using testosterone implants placed subdermally 6 days prior to orchiectomy. Collectively, these results illustrate that a physiological link does indeed exist between the testis and the liver, and that testes per se can influence the liver in vivo
2-MG expression in response to inflammation possibly via testosterone or testosterone-induced biological factor(s).
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