Degeneration of spermatocytes during meiotic divisions in the golden hamster testis.
The appearance and morphology of spontaneously degenerating meiotic spermatocytes was studied in late pubertal golden hamster testes by high resolution light and electron microscopy. While degeneration of primary spermatocytes during the long prophase of meiosis I is chiefly confined to midpachytene cells in stages VII-VIII of the seminiferous cycle, the subsequent meiotic phases (and their degenerative disorders) appear side by side in stage XIII of the cycle. Degeneration regularly concerns, in decreasing order of frequency, midpachytene primary spermatocytes (prophase I), metaphases I/II, telophases I/II, prophase II, and anaphases I/II. This closely corresponds to the apparent durations of these respective phases. In all meiotic phases studied, degeneration follows the same morphological pattern, including an initial vacuolar transformation of the cytoplasm and accumulation of densely staining material along membranes and microtubules, a progressive condensation of all nuclear and cytoplasmic structures, and the final cellular disintegration. In meta- and anaphase cells, meiotic spindle fibres are often perceivable even in advanced stages of degeneration. Both the morphological uniformity of spermatocyte degeneration and the constant susceptibility of meiotic phases to degeneration throughout meiotic divisions point to a generally similar mechanism underlying the physiological loss of meiotic spermatocytes.
Miething
A
A
Institute of Anatomy, University of Bonn, Germany.
D000818:Animals; D006224:Cricetinae; D008297:Male; D008540:Meiosis; D008647:Mesocricetus; D013090:Spermatocytes / Q000166:cytology / Q000648:ultrastructure*; D013737:Testis / Q000166:cytology / Q000648:ultrastructure*