Transport of iron and transferrin synthesis by the seminiferous epithelium of the rat in vivo.
Transport of iron and transferrin synthesis by the seminiferous epithelium of the rat in vivo.
复制标题
大鼠体内生精上皮的铁转运和转铁蛋白合成。
DOI：
10.1095/biolreprod37.4.995
复制
发表时间：
1987
影响因子：
3.6
通讯作者：
Griswold,MD
中科院分区：
文献类型：
--
作者：
Morales,C;Sylvester,SR;Griswold,MD
通过光镜定量放射自显影法分析了放射性铁在生精小管中的转运。在5分钟后，一个单一的睾丸内注射55铁-转铁蛋白，一个强有力的标记的生精上皮的基底方面进行了观察。在30 min和2 h之间，生精上皮基底面的标记减少。这种减少伴随着近腔室中细胞成分的放射自显影反应的大幅增加。这些结果与59 Fe-转铁蛋白注射睾丸后用速度沉降法分离的减数分裂精母细胞和分化中的精子细胞中的59 Fe有关的证明一致。此外，单次睾丸内注射59 Fe标记的人转铁蛋白后，放射性标记的大鼠转铁蛋白与特异性抗体从分离的肾小管匀浆中免疫沉淀，并在尿素/聚丙烯酰胺凝胶荧光照片上显示为单一的放射性条带。同样地，59 Fe标记的大鼠转铁蛋白而不是125 I标记的转铁蛋白从注入59 Fe或125 I标记的人转铁蛋白的睾丸网液中免疫沉淀。最后，在通过结扎肝动脉和门静脉将肝脏排除在全身循环之外的大鼠中，在睾丸内注射35 S-蛋氨酸后，免疫沉淀转铁蛋白的荧光照片证实了体内睾丸转铁蛋白的合成。因此，我们的结果证明了铁从生精上皮的基底室到近腔室中的生殖细胞的单向运输系统，涉及两种不同的转铁蛋白，即，由生精上皮合成的血清转铁蛋白和睾丸转铁蛋白。
The transport of radioactive iron across the seminiferous tubules was analyzed in vivo by light-microscope quantitative radioautography. At 5 min after a single intratesticular injection of55Fe-transferrin, a strong labeling of the basal aspect of the seminiferous epithelium was observed. Between 30 min and 2 h, the labeling on the basal aspect of the seminiferous epithelium decreased. This decrease was accompanied by a substantial increase of the radioautographic reaction over the cellular elements in the adluminal compartment. These results were consistent with the demonstration of59Fe associated with meiotic spermatocytes and differentiating spermatids isolated by velocity sedimentation from testes injected with59Fe-transferrin. Furthermore, after a single intratesticular injection of59Fe-labeled human transferrin, radiolabeled rat transferrin was immunoprecipitated from homogenates of isolated tubules with a specific antibody and appeared as a single radioactive band on fluorographs of urea/polyacrylamide gels. Similarly,59Fe-labeled rat transferrin but not125I-transferrin was immunoprecipitated from rete testis fluids of testes infused with either59Fe- or125I-labeled human transferrin. Finally, the synthesis of testicular transferrin in vivo was demonstrated in fluorographs of immunoprecipitated transferrin after an intratesticular injection of35S-methionine in rats whose livers were excluded from the general circulation by ligation of both the hepatic artery and the portal vein. Thus, our results demonstrated a unidirectional system of iron transport from the basal compartment of the seminiferous epithelium to the germ cells in the adluminal compartment involving two distinct transferrins, i.e., a serum transferrin and a testicular transferrin synthesized by the seminiferous epithelium.