Delgado M J, Gutiérrez P, Alonso-Bedate M
Departamento de Biología Animal II (Fisiologia), Facultad de Biología, Universidad Complutense, Madrid, Spain.
Gen Comp Endocrinol. 1989 Jan;73(1):1-11. doi: 10.1016/0016-6480(89)90049-x.
Studies of seasonal testicular cycle based on spermatogenetic activity and direct measurement of plasma testosterone were made in male frog Rana perezi obtained from its natural biotope in the Iberian Peninsula. Testosterone plasma level was determined by radioimmunoassay and exhibited notable differences according to season: plasma testosterone was lowest (less than 0.5 ng/ml) in summer and then increased progressively to reach a peak in spring (3-4 ng/ml), coincident with mating. After spermiation, when an increase in temperature and photoperiod in the natural habitat occurs, levels decline. Fat bodies also show a pronounced seasonal cycle with total regression following breeding and maximal development in winter. However, testicular weight was independent of seasons, and no significant change was observed throughout the year. Histological evidence indicates that although cell nests of different types are present every month of the year, the most important spermatogenetic activity is initiated in summer. The possible relationship between spermatogenetic activity and testosterone production and the importance of environmental factors as synchronizers of seasonal reproduction are discussed.
基于精子发生活性以及血浆睾酮直接测定，对从伊比利亚半岛自然栖息地获取的雄性泽蛙的季节性睾丸周期展开了研究。通过放射免疫分析法测定血浆睾酮水平，结果显示其随季节呈现显著差异：夏季血浆睾酮水平最低（低于0.5纳克/毫升），随后逐渐升高，在春季达到峰值（3 - 4纳克/毫升），这与交配期相符。排精后，随着自然栖息地温度和光周期的增加，睾酮水平下降。脂肪体也呈现出明显的季节性周期，繁殖后完全退化，冬季发育至最大程度。然而，睾丸重量不受季节影响，全年未观察到显著变化。组织学证据表明，尽管一年中每个月都存在不同类型的细胞巢，但最重要的精子发生活动始于夏季。文中还讨论了精子发生活动与睾酮产生之间的可能关系，以及环境因素作为季节性繁殖同步器的重要性。
