生长激素释放肽促生长的免疫调节

采用固相法合成了生长激素释放肽（ＧＨＲＰ）,研究了其促生长及免疫调节活性,腹腔连续注射（ｉｐ）１００,３００,１０００,５０００μｇ／ｋｇ ＧＨＲＰ１０ｄ后,发现小鼠体重对照组显明增加;复腔连续细胞（ＰＭΦ）精氨酸酶（Ａｒｇｉａｓｅ）,酸性磷酸酶（ＡＣＰ）活性提高约５０％;红细胞Ｃ３ｂＲ及ＩＣ花环率、血清溶血素含量增加８０％左右,提示ＧＨＲＰ具有免疫调节活性。     

Melatonin biosynthesis in the thymus of humans and rats

Melatonin is an indoleamine widely distributed in the evolution that shows a great functional versatility, playing an important role as a transmitter of photoperiodic information and exhibiting antioxidant, oncostatic, anti-aging and immunomodulatory properties. In vertebrates, this molecule is produced by the pineal gland and other extrapineal sites. The present study was carried out to investigate the presence of melatonin in thymus and the possibility of an endogenous melatonin synthesis in this organ, in which T cells are matured. In this work, we demonstrate in humans and rats that thymus contains melatonin, expresses the mRNAs encoding N-acetyltransferase and hydroxyindol-O-methyltransferase, the two key enzymes of the melatonin synthesis, and has this biosynthetic machinery activated. In addition, rat thymocytes cultured for 24 h exhibited high levels of melatonin. The results presented here suggest that human and rat thymuses are able to synthesize melatonin, which could have intracrine, autocrine and paracrine functions. Received 30 September 2006; received after revision 30 December 2006; accepted 15 February 2007