Scott I, Hodgkinson S M, Lawton D E, Khalaf S, Reynolds G W, Pomroy W E, Simpson H V
College of Sciences, Massey University, Palmerston North, New Zealand.
Int J Parasitol. 1998 Sep;28(9):1393-401. doi: 10.1016/s0020-7519(98)00112-x.
Gastric endocrine cell populations and serum and tissue gastrin have been examined in sheep which were infected either intraruminally by tube with 150,000 Ostertagia circumcincta larvae followed by a trickle infection of 10,000 larvae thrice weekly for 8 weeks or by the transfer of 15,000 adult worms directly into the abomasum and killed 8 days later. Depletion of both antral gastrin and somatostatin was evident in both groups: tissue gastrin concentrations were reduced by 85% in the trickle infection and both G cells (gastrin-containing) and D cells (somatostatin-containing) were pale and fewer after adult worm transfer. The concurrent depletion of antral gastrin and somatostatin supports the contention that the hypergastrinaemia in parasitised sheep is largely secondary to the increase in abomasal pH. Although there was no change in the proportions of G34 and G17 in the tissues, there was an increase in the longer form of gastrin in the circulation of the larval-infected sheep, suggesting that there may be differential secretion of G17 and G34 which may be exaggerated as the rate of secretion increases. Although the fundic mucosa was thicker following trickle infection, there was no evidence of enterochromaffin-like cell hyperplasia in either infected group. It is suggested that hyper-gastrinaemia may be beneficial to the host, as it may allow the abomasum to regain the ability to acidify its contents during continued exposure to the parasites.
对绵羊的胃内分泌细胞群、血清和组织胃泌素进行了检测。这些绵羊要么通过瘤胃内插管感染150,000条环形奥斯特他线虫幼虫，随后每周三次以每次10,000条幼虫进行连续感染，持续8周；要么直接将15,000条成虫转移至皱胃，并在8天后处死。两组绵羊的胃窦胃泌素和生长抑素均明显减少：连续感染组的组织胃泌素浓度降低了85%，成虫转移组中，含胃泌素的G细胞和含生长抑素的D细胞均颜色变淡且数量减少。胃窦胃泌素和生长抑素同时减少，支持了寄生绵羊高胃泌素血症主要继发于皱胃pH值升高这一观点。尽管组织中G34和G17的比例没有变化，但幼虫感染绵羊的循环中胃泌素的较长形式增加，这表明G17和G34可能存在差异分泌，且随着分泌速率增加这种差异可能会扩大。尽管连续感染后胃底黏膜变厚，但在任何一个感染组中均未发现肠嗜铬样细胞增生的证据。研究表明，高胃泌素血症可能对宿主有益，因为它可能使皱胃在持续接触寄生虫期间恢复酸化其内容物的能力。
