Bigaj J, Płytycz B
Thymus. 1984;6(6):369-73.
In European common frogs, Rana temporaria, leading an active land life at high external temperatures (May-October), the thymus glands are clearly divided into lymphocyte-rich cortex and mainly epithelial medulla ('summer' appearance). In contrast, thymuses of hibernating and mating frogs (at low temperatures, October-April) are typically endocrine organs with an abundant population of secretory cells, small number of thymocytes and lack cortico-medullary division ('winter' appearance). Thymuses of experimental animals kept from September until January at a high temperature tend to change their appearance from the 'summer' type to the 'winter' one. Thymuses of experimental frogs kept from the end of May until the end of June in refrigerator preserve their 'summer' appearance. These results show that the annual rhythm of the frog thymus gland is difficult to alter by simple changes of external temperature.
在欧洲普通青蛙（林蛙）中，其在较高外界温度下（5月至10月）过着活跃的陆地生活，胸腺明显分为富含淋巴细胞的皮质和主要为上皮细胞的髓质（“夏季”外观）。相比之下，冬眠和交配期青蛙的胸腺（在低温下，10月至4月）通常是内分泌器官，有大量分泌细胞，胸腺细胞数量少且缺乏皮质 - 髓质区分（“冬季”外观）。9月至1月在高温下饲养的实验动物的胸腺往往会从“夏季”型外观转变为“冬季”型外观。5月底至6月底在冰箱中饲养的实验青蛙的胸腺保持其“夏季”外观。这些结果表明，青蛙胸腺的年度节律很难通过外界温度的简单变化而改变。
