Martínez-Fuentes A J, Malagón M M, Castaño J P, Garrido-Gracia J C, Gracia-Navarro F
Department of Cell Biology, University of Córdoba, Spain.
Life Sci. 1998;62(26):2379-90. doi: 10.1016/s0024-3205(98)00220-3.
Pituitary adenylate cyclase-activating polypeptide (PACAP) has been suggested to regulate growth hormone (GH) secretion in several species. Here, we analyzed the in vitro effects of PACAP38 and PACAP27 on the secretory activity of porcine somatotropes. Cultures of porcine pituitary cells were treated with PACAP38 and PACAP27, and GH release, intracellular GH content, and GH mRNA levels were evaluated. Also, the time course of changes in the somatotrope content of GH and its mRNA in response to PACAPs were measured. Both PACAPs stimulated GH release from porcine somatotropes in a broad range of doses (10(-10)-10(-6) M), yet only PACAP27 elicited a dose-dependent response. GH cell content remained essentially unchanged after PACAP treatment. In contrast, both PACAPs induced significant and sustained increases in GH mRNA cell content, although the response to PACAP27 appeared faster (8 h) than to PACAP38 (16 h). These results demonstrate that PACAP stimulates GH production in porcine somatotropes. Furthermore, the differential responses induced by PACAP38 and PACAP27 suggest that distinct mechanisms mediate their effects on this cell type.
垂体腺苷酸环化酶激活多肽（PACAP）已被认为在多个物种中调节生长激素（GH）的分泌。在此，我们分析了PACAP38和PACAP27对猪生长激素细胞分泌活性的体外影响。用PACAP38和PACAP27处理猪垂体细胞培养物，并评估GH释放、细胞内GH含量和GH mRNA水平。此外，还测量了生长激素细胞中GH及其mRNA含量响应PACAPs变化的时间进程。两种PACAPs均在广泛的剂量范围（10^(-10)-10^(-6) M）内刺激猪生长激素细胞释放GH，但只有PACAP27引起剂量依赖性反应。PACAP处理后GH细胞含量基本保持不变。相反，两种PACAPs均诱导GH mRNA细胞含量显著且持续增加，尽管对PACAP27的反应（8小时）比对PACAP38的反应（16小时）出现得更快。这些结果表明，PACAP刺激猪生长激素细胞产生GH。此外，PACAP38和PACAP27诱导的不同反应表明，不同的机制介导了它们对这种细胞类型的作用。
