Michalkiewicz M, Huffman L J, Dey M, Hedge G A
Department of Physiology, West Virginia University Health Sciences Center, Morgantown 26506.
Am J Physiol. 1994 Jun;266(6 Pt 1):E905-13. doi: 10.1152/ajpendo.1994.266.6.E905.
Vasoactive intestinal peptide (VIP) is present in thyroid parasympathetic nerves. To assess the involvement of endogenous VIP in the regulation of thyroid function, blood levels of thyroid hormones and thyroid blood flows (TBF) were measured after systemic immunization against VIP or after transection of the superior laryngeal nerves in male rats, which reduced the thyroid content of VIP but did not affect blood levels of thyroid hormones or TBF. Anti-VIP monoclonal antibody or anti-VIP serum was used for immunization against VIP in normal rats. In addition, VIP antibody was given to rats fed an iodine-deficient diet for 5 days to examine the involvement of this peptide in iodine deficiency-induced increases in TBF. Effects were measured at different times (90 s, 30 min, 1 h, and 5 days) after immunoneutralization, but none of these treatments changed blood levels of thyroid hormones or TBF in normal or iodine-deficient rats. However, passive immunization against VIP was associated with a high binding capacity of rat plasma to VIP, and this treatment reduced blood levels of prolactin as well as blood flows to the duodenum, stomach, and lung. These findings suggest that the VIP present in thyroid nerves is not involved in maintaining basal thyroid hormone secretion or TBF and that this neuropeptide does not mediate thyroid vascular adjustments to dietary iodine deficiency.
血管活性肠肽（VIP）存在于甲状腺的副交感神经中。为评估内源性VIP在甲状腺功能调节中的作用，在对雄性大鼠进行针对VIP的全身免疫后，或在切断喉上神经后，测量甲状腺激素的血药浓度和甲状腺血流量（TBF），切断喉上神经可降低甲状腺中的VIP含量，但不影响甲状腺激素的血药浓度或TBF。在正常大鼠中，使用抗VIP单克隆抗体或抗VIP血清对VIP进行免疫。此外，给喂食缺碘饮食5天的大鼠注射VIP抗体，以检查该肽在碘缺乏诱导的TBF增加中的作用。在免疫中和后的不同时间点（90秒、30分钟、1小时和5天）测量效果，但这些处理均未改变正常或缺碘大鼠的甲状腺激素血药浓度或TBF。然而，针对VIP的被动免疫与大鼠血浆对VIP的高结合能力有关，这种处理降低了催乳素的血药浓度以及十二指肠、胃和肺的血流量。这些发现表明，甲状腺神经中存在的VIP不参与维持基础甲状腺激素分泌或TBF，并且这种神经肽不介导甲状腺血管对饮食碘缺乏的调节。
