Ogwuegbu S O, Hashizume T, Kanematsu S
Laboratory of Animal Reproduction, Faculty of Agriculture, Iwate University, Morioka, Japan.
Domest Anim Endocrinol. 1991 Jan;8(1):29-35. doi: 10.1016/0739-7240(91)90037-k.
The effect of vasoactive intestinal peptide (VIP) on the release of growth hormone (GH) from the adenohypophysis of the goat was studied in vitro using the perifusion system. Two perifusion systems were employed to differentiate potential direct effects of VIP on the pituitary from indirect effects mediated through the hypothalamus. The first perifusion system used single chambers housing only pituitary fragments. The second system used two chambers in tandem, one containing hypothalamus and the second the pituitary fragments, the flow passing through the hypothalamic chamber first. VIP (10(-6), 10(-7), 10(-8)M) stimulated significant GH release in both perifusion systems (P less than 0.05, P less than 0.01) in a concentration related fashion. The quantity of GH release induced by the 10(-9)M and 10(-10)M VIP groups were not significant. Further, the GH released from the system that perifused the pituitary alone (10(-8)M VIP) was significantly higher than that containing both the hypothalamus and the pituitary fragments (P less than 0.05). The relative lower GH secretory response to the same dose of VIP applied to the hypothalamus-pituitary suggests that the perifused caprine hypothalamus may release an inhibitory factor, such as somatostatin in vitro. These results suggest that VIP stimulates GH release by acting directly on the adenohypophysis of the goat.
采用灌流系统在体外研究了血管活性肠肽（VIP）对山羊腺垂体生长激素（GH）释放的影响。使用了两种灌流系统来区分VIP对垂体的潜在直接作用与通过下丘脑介导的间接作用。第一种灌流系统使用仅容纳垂体碎片的单腔室。第二种系统串联使用两个腔室，一个包含下丘脑，另一个包含垂体碎片，灌流液先流经下丘脑腔室。VIP（10^(-6)、10^(-7)、10^(-8)M）以浓度相关的方式刺激了两种灌流系统中显著的GH释放（P<0.05，P<0.01）。10^(-9)M和10^(-10)M VIP组诱导的GH释放量不显著。此外，仅灌流垂体的系统（10^(-8)M VIP）释放的GH显著高于包含下丘脑和垂体碎片的系统（P<0.05）。对灌流的下丘脑 - 垂体给予相同剂量的VIP时，GH分泌反应相对较低，这表明灌流的山羊下丘脑在体外可能释放一种抑制因子，如生长抑素。这些结果表明，VIP通过直接作用于山羊的腺垂体来刺激GH释放。
