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采用5头装有瘤胃瘘管、十二指肠瘘管的土著种成年空怀母山羊,按自身对照设计,试验期山羊皮下注射孕酮1.25MG/D,以研究孕酮对瘤胃微生物氮代谢的调节及其作用机理.结果表明,皮下注射孕酮可进入瘤胃,并影响微生物的代谢活动,使十二指肠食糜微生物氮(MCP－N),尿素氮(UN),氨氮(NH3－N)量极显著增加(P＜0.01),但食糜总氮,过瘤胃蛋白氮(BPN)或非氨氮(NAN)无显著变化(P＞0.05).用放射免疫受体测定法对瘤胃细菌进行测定,发现山羊瘤胃细菌孕酮受体(BPR)与孕酮的最大结合容量和KD值分别为105.01±15.32MOL/MG(蛋白)和9.54±0.44*10－8MOL/L(N＝3).非标记孕酮对BPR的竟争抑制作用明显.上述结果显示,进入瘤胃的孕酮可与微生物受体结合,继发一系列生理生化反应,使瘤胃微生物对内源氮的利用增加,在提高MCP合成量的同时,不见减少BPN.因此,孕酮对瘤胃微生物氮代谢具有双向调节作用.“,”In this experiment five native female goats fitted with chronic rumen fistulas,T?shaped duodenal cannulas were used to study the regulation of the ruminal nitrogen metabolism by injecting progesterone subcutandously(1?25mg/kg body weight),and to assay the ruminal bacteria progesterone receptor.The study showed that compared with the control period,the progesterone entered the rumen through blood and reached its peak 8 hours after the injection.Goat intake,duodenal chyme flow,as well as the microbe?nitrogen(...