Houben H, Denef C
Laboratory of Cell Pharmacology, University of Leuven School of Medicine, Belgium.
Endocrinology. 1991 Jun;128(6):3208-18. doi: 10.1210/endo-128-6-3208.
Using antisera raised against the N-terminal (1-16) or the C-terminal part of the bombesin (BBN)-like peptide gastrin-releasing peptide (GRP) and against the C-terminus of pro-GRP, GRP- and pro-GRP-like immunoreactivity (IR) was detected by immunostaining in freshly dispersed rat anterior pituitary (AP) cells and in reaggregate AP cells cultured in serum-free medium. Depending on the antiserum used, 6.4 +/- 0.4% to 12.4 +/- 2.7% of freshly dispersed cells were immunoreactive. Solid phase preabsorption of the antisera with the respective antigens abolished the staining. GRP-IR was detectable by double immunostaining in a subpopulation of PRL cells and ACTH-containing cells. In contrast, only very few somatotrophs, gonadotrophs, and thyrotrophs were immunoreactive, and they were much smaller than the typical mature forms of these cell types. GRP- and pro-GRP-IR were also detected in the ACTH-secreting AtT20 cell line and in the PRL- and GH-secreting GH3 cell line. GRP- and pro-GRP-IR were present in AP cell aggregates maintained in culture for 4 weeks. The finding of both GRP- and pro-GRP-IR in a subpopulation of lactotrophs and corticotrophs and their persistence in culture under serum-free conditions strongly suggest that GRP-like peptides are produced in rat AP. Although the potent GRP receptor antagonist L 686,095-001C002 effectively blocks stimulation of GH and PRL release by exogenous BBN-like peptides, it failed to affect basal GH and PRL release from perifused reaggregate AP cell cultures as well as GH and/or PRL release stimulated by epinephrine, vasoactive intestinal peptide, TRH, GH-releasing factor, and angiotensin-II or PRL release inhibited by dopamine. Thus, the latter data do not support the hypothesis often suggested that peptides endogenously present in AP cells are involved in the paracrine regulation of AP hormone secretion.
利用针对胃泌素释放肽（GRP）（一种类似蛙皮素（BBN）的肽）的N端（1 - 16）或C端部分以及pro - GRP的C端产生的抗血清，通过免疫染色在新鲜分散的大鼠垂体前叶（AP）细胞和无血清培养基中培养的重新聚集的AP细胞中检测到了GRP和pro - GRP样免疫反应性（IR）。根据所用抗血清的不同，6.4±0.4%至12.4±2.7%的新鲜分散细胞具有免疫反应性。用相应抗原对抗血清进行固相预吸收可消除染色。通过双重免疫染色在一部分催乳素（PRL）细胞和促肾上腺皮质激素（ACTH）细胞中可检测到GRP - IR。相比之下，只有极少数生长激素细胞、促性腺激素细胞和促甲状腺激素细胞具有免疫反应性，并且它们比这些细胞类型的典型成熟形式小得多。在分泌ACTH的AtT20细胞系以及分泌PRL和生长激素（GH）的GH3细胞系中也检测到了GRP和pro - GRP - IR。在培养4周的AP细胞聚集体中存在GRP和pro - GRP - IR。在一部分泌乳细胞和促肾上腺皮质激素细胞中发现GRP和pro - GRP - IR以及它们在无血清条件下培养时的持续存在，强烈表明大鼠AP中产生了类似GRP的肽。尽管强效的GRP受体拮抗剂L 686,095 - 001C002有效地阻断了外源性类似BBN的肽对GH和PRL释放的刺激，但它未能影响来自经灌注的重新聚集的AP细胞培养物的基础GH和PRL释放，以及肾上腺素、血管活性肠肽、促甲状腺激素释放激素（TRH）、生长激素释放因子和血管紧张素 - II刺激的GH和/或PRL释放，或多巴胺抑制的PRL释放。因此，后一组数据不支持常被提出的假设，即AP细胞内源性存在的肽参与AP激素分泌的旁分泌调节。
