Zitouni M, Pévet P, Masson-Pévet M
URA CNRS 1332, Université Louis Pasteur, Strasbourg, France.
J Neuroendocrinol. 1996 Aug;8(8):571-7.
Using quantitative autoradiography, melatonin receptors have been studied during post-natal and pubertal development of the rat in 2 brain and 2 pituitary structures. In the pars distalis of anterior pituitary, melatonin receptors decrease gradually in density after birth and disappear in 30 day-old animals. In contrast melatonin binding is only expressed in the paraventricular nuclei of the thalamus at the age of 21-23 days and is always present in adult animals. In the suprachiasmatic nuclei and in the pars tuberalis of the pituitary, melatonin receptor density decreases after birth, remains stable for approximately 1 month and increases again at puberty to reach the birth values in the adult. This increase was absent in pinealectomized and in castrated animals but present in castrated animals receiving testosterone suggesting that it depends upon circulating testosterone and melatonin levels. These results show that melatonin receptors are differentially regulated during post-natal development in each of the 4 structures studied, and that melatonin and testosterone are 2 factors which could be involved in the regulation of melatonin receptor density in the suprachiasmatic nuclei and pars tuberalis.
利用定量放射自显影技术，对出生后及青春期大鼠的2个脑区和2个垂体结构中的褪黑素受体进行了研究。在垂体前叶远侧部，出生后褪黑素受体密度逐渐降低，在30日龄动物中消失。相比之下，褪黑素结合仅在21 - 23日龄时在丘脑室旁核中表达，且在成年动物中一直存在。在视交叉上核和垂体结节部，出生后褪黑素受体密度降低，约1个月保持稳定，青春期时再次升高，在成年时达到出生时的水平。这种增加在松果体切除的动物和去势动物中不存在，但在接受睾酮的去势动物中存在，表明它取决于循环中的睾酮和褪黑素水平。这些结果表明，在所研究的4个结构中，出生后发育过程中褪黑素受体受到不同的调节，并且褪黑素和睾酮是可能参与调节视交叉上核和结节部褪黑素受体密度的两个因素。
