Mosconi Gilberto, Cardinali Marco, Yamamoto Kazutoshi, Kikuyama Sakae, Vellano Camillo, Polzonetti-Magni Alberta Maria
Department of Comparative Morphology and Biochemistry, University of Camerino, Via F. Camerini 2, 62032 Camerino MC, Italy.
Gen Comp Endocrinol. 2002 May;126(3):261-8. doi: 10.1016/s0016-6480(02)00001-1.
The effects of temperature on pituitary prolactin (PRL) gene expression and peripheral levels were studied in both male and female newts obtained from wild conditions during reproductive (Experiment I) and nonreproductive (Experiment II) periods; moreover, changes in parameters related to reproductive function are also described. Male and female newts were taken from a pond in February (Experiment I, reproductive period) and maintained for 1 month in tanks at 4 and 18 degrees C. In male newts kept at 4 degrees C, increase of PRL mRNA in the pituitary and plasma PRL was found compared with that measured in those kept at 18 degrees C. The increase in PRL secretion was parallel to that of plasma androgens and related secondary sexual characteristics (SSC) in males and of plasma estradiol-17beta and vitellogenin in females. On the contrary, in nonreproductive newts (Experiment II), taken from the field in May, no significant changes in plasma PRL, androgens, and SSC were found in those maintained at low temperature (4 degrees C), whereas low temperature significantly increased PRL mRNA expression in the male pituitary and PRL mRNA plus plasma PRL levels in females. These findings suggest that low temperature regulates PRL secretion in this urodele species, showing a sex- and season-related control mechanism; moreover, low temperature failed to influence the reproductive biology of newts taken from the field in May, after naturally occurring reproduction during winter months.
研究了温度对野生环境中获取的雄性和雌性蝾螈在繁殖期（实验一）和非繁殖期（实验二）垂体催乳素（PRL）基因表达及外周水平的影响；此外，还描述了与生殖功能相关参数的变化。雄性和雌性蝾螈于二月从一个池塘捕获（实验一，繁殖期），并在4摄氏度和18摄氏度的水箱中饲养1个月。在4摄氏度饲养的雄性蝾螈中，与18摄氏度饲养的相比，垂体中PRL mRNA和血浆PRL增加。PRL分泌的增加与雄性血浆雄激素及相关第二性征（SSC）以及雌性血浆雌二醇-17β和卵黄蛋白原的增加平行。相反，在五月从野外捕获的非繁殖蝾螈（实验二）中，低温（4摄氏度）饲养的蝾螈血浆PRL、雄激素和SSC无显著变化，而低温显著增加了雄性垂体中PRL mRNA的表达以及雌性PRL mRNA和血浆PRL水平。这些发现表明，低温调节这种有尾目动物的PRL分泌，显示出一种与性别和季节相关的控制机制；此外，低温并未影响五月从野外捕获的蝾螈在冬季自然繁殖后的生殖生物学。
