摘要:
The urotoxins (Glu-Asp-Gly-OH, His-Gly-Glu-OH, His-Gly-Lys-OH, and His-Gly-Lys-NHNH2) were introduced into the convenient sites of hydrocortisone and prednisolone via the amidation or condensation reactions to form the corresponding linkers 7a-d, 8a-d, 9a,b, and 10a,b in acceptable yields. The bioassays such as prolongation of heterotopic transplanted cardiac tissue survival in vivo, inhibitory effects on phagocytosis of mouse peritoneal macrophages and concanavalin (ConA) or lipopolysaccharide (LPS) induced proliferation of mouse spleen lymphocytes in vitro show that at the comparable concentrations the immuno suppressive activities of the steroid-urotoxin linkers 7a-d, 8a-d, 9a,b, and 10a,b were higher than that of hydrocortisone, prednisolone, and the urotoxins alone, as well as significantly higher than that of the mixture of hydrocortisone and urotoxins or prednisolone and urotoxins. The so-called 'permissive action' may be responsible for the enhancement of the mentioned bioactivities of the steroid-urotoxin linkers 7a-d, 8a-d, 9a,b, and 10a,b. (C) 2004 Elsevier Ltd. All rights reserved.