caa a22 4500 469082259 CHVBK 20180323132954.0 cr unu---uuuuu 170328e19920101xx s 000 0 eng 10.1007/BF00318690 doi (NATIONALLICENCE)springer-10.1007/BF00318690 Receptor-mediated endocytosis of testicular transferrin by germinal cells of the rat testis [Elektronische Daten] [Robert Petrie Jr., Carlos Morales] Summary: The present study examines events of the Sertoli cell iron delivery pathway following the secretion of diferric testicular transferrin (tTf) into the adluminal compartment of the rat seminiferous epithelium. The unidirectional secretion of tTf by Sertoli cells was verified, in vivo, and it was shown that this protein is internalized by adluminal germ cells. It was further determined by Scatchard analysis that this internalization was mediated by high affinity transferrin binding sites on the surface of round spermatids, numbering 1453/cell and displaying a Kd=0.6×10-9 M. Northern blot analysis of RNA isolated from adluminal germ cells, namely spermatocytes, round spermatids and elongating spermatids, indicated that these cells expressed Tf receptor mRNA and ferritin mRNA in levels inversely related to their stage of maturation. Finally it was determined that following binding and internalization in round spermatids, Tf became associated with the endosomal compartment and was recycled back to the cell surface. This study illustrates the immediate fate of tTf once it is secreted by the Sertoli cell. Thus, diferric tTf binds of Tf receptor on the surface of adluminal germ cells, is internalized by receptor-mediated endocytosis and the apo Tf-Tf receptor complex is recycled back to the cell surface where apotTf is released into the adluminal fluid. Springer-Verlag, 1992 Transferrin nationallicence Transferrin receptor nationallicence Ferritin nationallicence Gerrninal cells nationallicence Sertoli cells nationallicence Rat (Sprague-Dawley) nationallicence Petrie Jr. Robert Department of Anatomy, McGill University, 3640 University Street, H3A 2B2, Montreal, Quebec, Canada aut Morales Carlos Department of Anatomy, McGill University, 3640 University Street, H3A 2B2, Montreal, Quebec, Canada aut Cell and Tissue Research Springer-Verlag 267/1(1992-01-01), 45-55 0302-766X 267:1<45 1992 267 441 https://doi.org/10.1007/BF00318690 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00318690 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Petrie Jr Robert Department of Anatomy, McGill University, 3640 University Street, H3A 2B2, Montreal, Quebec, Canada aut NATIONALLICENCE 700 1- Morales Carlos Department of Anatomy, McGill University, 3640 University Street, H3A 2B2, Montreal, Quebec, Canada aut NATIONALLICENCE 773 0- Cell and Tissue Research Springer-Verlag 267/1(1992-01-01), 45-55 0302-766X 267:1<45 1992 267 441 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer