Kimura I, Sasamura T, Tsuneki H, Iwai M, Furuta I, Sasamoto H, Furusawa Y
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani, Japan.
Biol Pharm Bull. 1998 May;21(5):506-12. doi: 10.1248/bpb.21.506.
Human saliva contains a proline-rich polypeptide, salivary peptide P-C, which potentiates insulin release and reduces glucagon release from perfused rat pancreas to decrease blood glucose level. To elucidate the process of secretion into humoral fluid of this peptide morphologically, we investigated ultrastructural localization of P-C in human submandibular gland by immunogold technique with anti-peptide P-C whose specificity to P-C was confirmed by immunoblotting. The labeling with gold particles which represents the distribution of P-C-like-immunoreactivity (P-C-LI) was detected in the secretory granules and rough endoplasmic reticula of the acinar serous cells and in few mucosa cells. P-C-LI was also observed in the lumen of striated duct but not intracellularly in the ductal cells themselves, indicating that P-C is not probably reabsorbed there. These results suggest that salivary peptide P-C is present in acinar serous cells, is secreted into the oral cavity, and may be reabsorbed through the digestive tract to modulate the blood glucose level after feeding.
人类唾液中含有一种富含脯氨酸的多肽，即唾液肽P-C，它能增强胰岛素释放，并减少灌注大鼠胰腺中胰高血糖素的释放，从而降低血糖水平。为了从形态学上阐明这种肽分泌到体液中的过程，我们采用免疫金技术，用抗肽P-C对人下颌下腺中P-C的超微结构定位进行了研究，该抗肽P-C对P-C的特异性已通过免疫印迹法得到证实。在浆液性腺泡细胞的分泌颗粒和粗面内质网以及少数黏膜细胞中检测到了代表P-C样免疫反应性（P-C-LI）分布的金颗粒标记。在纹状管腔中也观察到了P-C-LI，但在导管细胞内未观察到，这表明P-C可能不会在那里被重吸收。这些结果表明，唾液肽P-C存在于浆液性腺泡细胞中，分泌到口腔中，并且可能在进食后通过消化道被重吸收以调节血糖水平。
