Scharfmann R, Leduque P, Aratan-Spire S, Dubois P, Basmaciogullari A, Czernichow P
INSERM U30, Hôpital des Enfants Malades, Paris, France.
Endocrinology. 1988 Sep;123(3):1329-34. doi: 10.1210/endo-123-3-1329.
Two experimental systems were used to investigate the relationship between TRH content and peptidylglycine alpha-amidating monooxygenase (PAMase) activity of the neonatal rat pancreatic islets: freshly isolated islets from rats aged 1-14 days, and fetal islets maintained in culture for 3 weeks. TRH was present in freshly isolated islets and in newly formed fetal islets in culture. However, while the TRH concentration in freshly isolated islets measured by RIA followed the same ontogenic pattern as that in the total pancreas, peaking during the first week of life (78 pg/micrograms DNA on day 4) and decreasing thereafter to reach 4 pg/micrograms DNA on day 14, the TRH content of fetal islets in culture did not decrease with time (65 pg/micrograms DNA on day 1 and 80 pg/micrograms DNA after 3 weeks in culture). Similarly, using immunocytochemistry, immunoreactive cells were only seen at day 2 in freshly isolated islets. In contrast, in fetal islets, TRH cells were present throughout the culture period. In both experimental systems, TRH was localized in beta-cells. PAMase activity paralleled TRH concentration, peaking during the first week of life in freshly isolated islets and remaining unchanged in the fetal islets in culture. PAMase activity is, therefore, present in the endocrine pancreas. The results suggest that PAMase activity is a rate-limiting step in TRH biosynthesis in this tissue.
使用了两个实验系统来研究新生大鼠胰岛中促甲状腺激素释放激素（TRH）含量与肽基甘氨酸α-酰胺化单加氧酶（PAMase）活性之间的关系：从1至14日龄大鼠新鲜分离的胰岛，以及在培养中维持3周的胎儿胰岛。TRH存在于新鲜分离的胰岛以及培养中的新生胎儿胰岛中。然而，虽然通过放射免疫分析（RIA）测定的新鲜分离胰岛中的TRH浓度遵循与整个胰腺相同的个体发生模式，在出生后第一周达到峰值（第4天为78 pg/μg DNA），此后下降，至第14天达到4 pg/μg DNA，但培养中的胎儿胰岛的TRH含量并未随时间减少（培养第1天为65 pg/μg DNA，培养3周后为80 pg/μg DNA）。同样，使用免疫细胞化学方法，仅在新鲜分离胰岛的第2天观察到免疫反应性细胞。相比之下，在胎儿胰岛中，TRH细胞在整个培养期均存在。在两个实验系统中，TRH均定位于β细胞。PAMase活性与TRH浓度平行，在新鲜分离胰岛中出生后第一周达到峰值，而在培养的胎儿胰岛中保持不变。因此，PAMase活性存在于内分泌胰腺中。结果表明，PAMase活性是该组织中TRH生物合成的限速步骤。
