The distribution of type A spermatogonia was studied using drawings of cross-sectioned tubules at various stages of the spermatogenic cycle of perfusion-fixed, epoxy-embedded mouse testis. Spermatogonia were classified as either positioned opposite the interstitium or opposite the region where two tubules make contact or in a defined, intermediate region at which the two tubules diverged. At stage V, the population of type A spermatogonia, comprised of As through Aal cells, is randomly positioned around the periphery of the seminiferous tubule. The As through Aal population becomes nonrandomly distributed beginning at stage VI, being located primarily in regions where the tubule opposes the interstitium, and remains nonrandom through stage III of the next cycle. The A1 spermatogonia of stage VII, derived from most Apr and Aal spermatogonia, and the A2 spermatogonia of stage IX, derived from the A1 spermatogonia, are also nonrandomly positioned opposing the interstitium. However, the A3 population of stage XI becomes randomly distributed around the tubule. To our knowledge, these are the first data to show that the more primitive spermatogonial types (As to Aal) move to specific sites within the seminiferous tubule. Division of the regularly spaced, more primitive spermatogonia (As to Aal) leads to the spread of their progeny (A1 to A4) laterally along the base of the seminiferous tubule. The lateral spread from more or less evenly spaced foci ensures that spermatogenesis is conducted uniformly around the entire tubule. The data also suggest that the position of a seminiferous tubule in the mouse is stabilized in relationship to other seminiferous tubules.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.