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Vasoactive intestinal polypeptide and somatostatin in leucocytes
Abstract:
Vasoactive intestinal polypeptide (VIP) was measured in extracts from polymorphonuclear (PMN) and mononuclear (MN) leucocytes from 14 healthy persons and 12 pigs. In addition, extracts from PMN and MN cells from eight pigs were studied for possible contents of somatostatin. Immunoreactive VIP was present in the PMN and MN leucocytes from man and pigs with a significantly higher level in the MN cells. Similarly, immunoreactive somatostatin was found in both cell lines from pigs with a significant higher amount in the MN leucocytes. Furthermore, extracts from pure populations of human PMN and MN leucocytes were separately applied on a Sephadex G-50 Fine column, and VIP, somatostatin, secretin, GIP and motilin were measured in the eluted fractions. Only VIP and somatostatin were found to be present in detectable amounts. Immunoreactive VIP eluted corresponding to the elution volume for pure porcine VIP in extracts from both PMN and MN cells, while immunoreactive somatostatin eluted corresponding to the elution volume for the synthetic tetradecapeptide somatostatin in extracts from MN cells only. Possible physiological implications of these findings are briefly discussed.
Insights
Vasoactive intestinal polypeptide (VIP) and somatostatin were found in human and pig immune cells, with higher levels in mononuclear cells. These peptides may play roles in immune cell function.
Area of Science:
- Immunology
- Endocrinology
- Cell Biology
Background:
- Vasoactive intestinal polypeptide (VIP) and somatostatin are peptides with diverse physiological roles.
- Leukocytes, including polymorphonuclear (PMN) and mononuclear (MN) cells, are key components of the immune system.
Purpose of the Study:
- To investigate the presence and levels of VIP and somatostatin in human and porcine leukocytes.
- To characterize the elution profiles of these peptides from leukocyte extracts.
Main Methods:
- Extraction of VIP and somatostatin from PMN and MN leukocytes of humans and pigs.
- High-performance liquid chromatography (HPLC) using Sephadex G-50 Fine column for peptide separation.
- Radioimmunoassay (RIA) for quantifying immunoreactive VIP and somatostatin.
Main Results:
- Immunoreactive VIP was detected in both PMN and MN leukocytes from humans and pigs, with significantly higher concentrations in MN cells.
- Immunoreactive somatostatin was found in porcine PMN and MN leukocytes, also showing higher levels in MN cells.
- Peptide analysis confirmed the presence of VIP in both human cell types and somatostatin predominantly in MN cells, eluting similarly to authentic porcine VIP and synthetic somatostatin, respectively.
Conclusions:
- Human and porcine leukocytes contain VIP and somatostatin, suggesting potential roles for these peptides in immune cell function.
- The differential distribution of these peptides between PMN and MN leukocytes may indicate distinct functional implications.
- Further research is warranted to elucidate the precise physiological roles of VIP and somatostatin within leukocytes.