ISSN:
0002-9106
Schlagwort(e):
Life and Medical Sciences
;
Cell & Developmental Biology
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Medizin
Notizen:
To analyze the behavior of spermatogonia in the monkey, the cytological features, topographical arrangement and frequency of the two classes of type A (A1, A2) and the four classes of type B (B1-B4) spermatogonia were determined in dissected tubules, fixed in Carnoy, stained with hematoxylin and mounted “in toto.” The capacity of spermatogonia to divide was also analyzed in radioautographed testicular sections from an animal injected with tritiated thymidine.The type A1 spermatogonia, characterized by nuclei containing deeply stained, finely granulated chromatin, were found to be non-dividing elements. The type A2 spermatogonia, characterized by nuclei showing palely stained, coarsely granular chromatin, all divided in stages IX-X of the cycle of the seminiferous epithelium to yield equal numbers of new type A2 cells and type B1 spermatogonia. The type B1, as the other type B cells, were characterized by nuclei containing granules or flakes of deeply stained chromatin. While the type A2 spermatogonia remained dormant until stage IX of the following cycle, the type B1 cells all divided during stage XII to yield twice their number of type B2 spermatogonia. These, in stage II, divided to give twice as many type B3, which, in stage IV, divided to produce twice as many type B4 spermatogonia. Lastly, in stage VI, the latter elements all divided to yield spermatocytes.Thus, the type A1 spermatogonia, did not appear to be actively involved in the production of spermatocytes and were tentatively considered as “reserve stem cells;” the type A2 spermatogonia, were identified as “renewing stem cells.”
Zusätzliches Material:
5 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/aja.1001260106
Permalink
