Details

Autor(en) / Beteiligte

• BARNES, B. M
• KRETZMANN, M
• LICHT, P
• ZUCKER, I

Titel

The influence of hibernation on testis growth and spermatogenesis in the golden-mantled ground squirrel, Spermophilus lateralis

Ist Teil von

• Biology of reproduction, 1986-12, Vol.35 (5), p.1289-1297

Ort / Verlag

Madison, WI: Society for the Study of Reproduction

Erscheinungsjahr

1986

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• Testis size and spermatogenesis were monitored serially in individual golden-mantled ground squirrels before, during, and after the hibernation season. During hibernation, animals spent 81% of days in torpor at body temperatures of 3-4 degrees C. Torpor bouts of 6 days duration were interspersed with brief arousals from torpor during which animals were normothermic. In the 5 mo between December (when animals entered hibernation) and April (when torpor was spontaneously terminated), the estimated mass of testes increased gradually from 500 to 1100 mg, but spermatogenesis did not advance beyond pachytene spermatocytes, which were present before hibernation began. In contrast, during the month after torpor was terminated, testes increased rapidly to 3500 mg and after 31 days, spermatozoa were found in the epididymides. We suggest that the limited testis growth that occurred during the hibernation season was restricted to intervals during which squirrels were aroused from torpor. The major portion of gonadal growth and spermatogenesis in the laboratory, and presumably in the field, occurs after ground squirrels have regained the normothermic state. Since males are reproductively mature when first trapped in spring, these findings suggest that males are normothermic for several weeks before they emerge from their hibernacula in the spring.