摘要： 采用5头装有瘤胃瘘管、十二指肠瘘管的土着种成年空怀母山羊，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）量极显着增加（P<0.01）,但食糜总氮，过瘤胃蛋白氮（BPN）或非氨氮（NAN）无显着变化（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。

关键词: 孕酮, 瘤胃氮代谢, 细菌孕酮受体

Abstract: 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(MCP N),UN and NH3 N in duodenal chyme,except for the total nitrogen,BPN and NAN,increased considerably(P<001).The radio receptor assay was used to analyse the progesterone receptor of goat rumen bacteria(BPR).The results showed that the maximal association content and Kd of BPR were 105.01±15.32 fmol/mg protein and 954±044×10 -8mol/L,respectively.It suggested that a certain specific progesterone receptor should exist in the ruminal bacteria.The results cited above showed that a series of bio effects could be stimulated by binding progesterone with BPR to obtain an increase both in the internal nitrogen and in MCP without affecting BPN.

Key words: Progesterone, Nitrogen metabolism of ruminal microorganisms, Bacteriaprogesterone receptor

中图分类号: 

• S852.2