Glucagon, glicentin, proglucagon, PYY, PP and proPP-icosapeptide immunoreactivities of rectal carcinoid tumors and related non-tumor cells.

Abstract

Glucagon/PP-related peptides were detected immunohistochemically in 18 out of 22 cases of rectal tumors investigated. The reactive tumors showed prevalence of trabecular or mixed trabecular-acinar structure and moderate staining with Grimelius' silver and lead-hematoxylin. Three of the remaining 4 cases were characterized by reactivity for 5-hydroxytryptamine only, prevalence of a solid nest structural component and intense staining with Grimelius' silver technique and lead-hematoxylin. Fifteen of the 18 glucagon/PP-reactive cases were investigated immunohistochemically with a series of 6 sera directed against different sequences of glucagon, glicentin and proglucagon, and of 7 sera directed against PP, PYY and proPP-icosapeptide. A large spectrum of glucagon-related immunoreactivities, including C-terminus and mid-portion glucagon-immunoreactivity, N- and C-terminus glicentin-immunoreactivity, GLP1- and GLP2-immunoreactivity, were detected in human rectal L cells and most rectal carcinoids. With the exception of a few scattered cells in the rectal mucosa and in 3 tumors, C-terminus glucagon-immunoreactivity was obtained only after trypsin or subtilisin treatment of tissue sections. Both PYY and PP/proPP-like peptide(s) were detected in rectal L cells and carcinoids, with prevalence of PYY in normal cells and PP/proPP-like peptides in tumor cells. It is concluded that the same or closely related hormone/prohormone sequences are synthesized and stored in rectal endocrine cells and carcinoid tumors although differences of quantitative expression, post-translational cleavage or reactivity to antibodies may occur. The usefulness of protease treatments of tissue sections to unmask immunoreactivities of uncleaved propeptides or fixative-denatured peptides is outlined.

• Authors: R Fiocca, G Rindi, C Capella, L Grimelius, J M Polak, T W Schwartz, N Yanaihara, E Solcia
• Journal: Regulatory peptides (Regul Pept) Vol. 17 Issue 1 Pg. 9-29 (Jan 1987) ISSN: 0167-0115 [Print] Netherlands
• PMID: 2882565 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Peptides
• Protein Precursors
• Peptide YY
• Serotonin
• Neurotensin
• Somatostatin
• Proglucagon
• Pancreatic Polypeptide
• Glucagon

Topics

• Animals
• Carcinoid Tumor (metabolism)
• Cattle
• Glucagon (metabolism)
• Humans
• Immunologic Techniques
• Neurotensin (metabolism)
• Pancreatic Polypeptide (metabolism)
• Peptide YY
• Peptides (metabolism)
• Proglucagon
• Protein Precursors (metabolism)
• Rectal Neoplasms (metabolism)
• Serotonin (metabolism)
• Somatostatin (metabolism)