Rettori V, Jurcovicova J, McCann S M
Department of Physiology, University of Texas Health Science Center, Dallas 75235.
J Neurosci Res. 1987;18(1):179-83. doi: 10.1002/jnr.490180125.
In order to determine the possible effects of interleukin-1 on the release of pituitary hormones by direct action on the brain, the peptide was injected into the third brain ventricle of conscious, unrestrained male rats and the effects on hormone release were compared with effects on rectal temperature. The procedure of blood sampling and intraventricular injection resulted in a significant decline in body temperature and a decrease in plasma growth hormone without alteration in the plasma level of thyroid stimulating hormone (TSH) and prolactin. Interleukin-1 injected intraventricularly at a dose of 5 ng (0.3 pmol) prevented the decline in body temperature that occurred in the saline-injected controls and resulted in a significant elevation of plasma growth hormone levels that became apparent within 15 min of injection, as well as a highly variable but significant elevation of plasma prolactin and a significant decline in plasma TSH that was observed at 30 min. The results were similar when areas under the release curves for the various hormones were calculated. On the other hand, the higher dose of 25 ng (1.5 pmole) of interleukin-1, although producing a frank pyrexia, was associated with smaller changes in hormone values, which were no longer significant for any of the three hormones. The results indicate that interleukin-1 can act in minute doses, presumably on structures near the third ventricle, to stimulate growth hormone and prolactin release and to inhibit TSH release. Apparently when frank febrile responses occur, these hormonal responses are muted for reasons that are yet to be determined. In view of the minute doses injected we favor a hypothalamic site for these effects.
为了确定白细胞介素-1通过直接作用于大脑对垂体激素释放可能产生的影响，将该肽注入清醒、不受束缚的雄性大鼠的第三脑室，并将其对激素释放的影响与对直肠温度的影响进行比较。采血和脑室内注射的操作导致体温显著下降以及血浆生长激素减少，而促甲状腺激素（TSH）和催乳素的血浆水平没有改变。以5纳克（0.3皮摩尔）的剂量脑室内注射白细胞介素-1可防止注射生理盐水的对照组中出现的体温下降，并导致血浆生长激素水平在注射后15分钟内显著升高，同时血浆催乳素出现高度可变但显著的升高，以及在30分钟时观察到血浆TSH显著下降。计算各种激素释放曲线下的面积时，结果相似。另一方面，25纳克（1.5皮摩尔）的较高剂量的白细胞介素-1虽然引起明显发热，但与激素值的较小变化相关，这三种激素中的任何一种变化都不再显著。结果表明，白细胞介素-1可以以微小剂量起作用，可能作用于第三脑室附近的结构，以刺激生长激素和催乳素释放并抑制TSH释放。显然，当出现明显的发热反应时，这些激素反应会因尚未确定的原因而减弱。鉴于注射的剂量微小，我们认为这些作用的部位在下丘脑。
