在内分泌系统中,脑垂体是无可争辩的冠军。研究发现,它能够比其他任何结构更加有力地控制身体的生长。日本一研究团队在美国《国家科学院院刊》(PNAS)上在线报道了此项成果。
不过现在,一个新的竞争者已经踏入了这场冠军的争夺战,虽然其手段有欠正当。
科学家们首次发现,至少在莫桑比克罗非鱼中,生殖腺扮演了“二级垂体”的角色,可以帮助鱼类长到成年个头。
这些生殖器官能够使雄性鱼产生精子,雌性鱼产生卵细胞。如果没有它们,这些鱼只能长到其普通大小的几分之一。
研究人员发现,将生殖腺移植回罗非鱼的体内,甚至是移植到一些无关紧要的部位诸如鱼的背脊,都能使这些鱼重新开始生长。
该研究小组报道称,这些发现或许适用于所有的脊椎动物,包括人类在内。
同时,这些发现对渔业来说也是一个福音。现在,养殖户们一直想尽各种办法,在养殖的鱼未长到可以作为食物前,不让鱼类进行繁殖。(生物谷Bioon.com)
doi:10.1073/pnas.1118704109
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Gonads directly regulate growth in teleosts
Sandip Bhattaa, Toshiharu Iwaia, Chiemi Miuraa, Masato Higuchia, Sonoko Shimizu-Yamaguchia, Haruhisa Fukadab, and Takeshi Miuraa
In general, there is a relationship between growth and reproduction, and gonads are known to be important organs for growth, but direct evidence for their role is lacking. Here, using a fish model, we report direct evidence that gonads are endocrine organs equal to the pituitary in controlling body growth. Gonadal loss of function, gain of function, and rescue of growth were investigated in tilapia. Gonadectomy experiments were carried out in juvenile males and females. Gonadectomy significantly retarded growth compared with controls; however, this retardation was rescued by the implantation of extirpated gonads. Because gonads express growth hormone, it is possible that gonads control body growth through the secretion of growth hormone and/or other endocrine factors. We propose that gonads are integral players in the dynamic regulation of growth in teleosts.