vasoactive-intestinal-peptide and Laryngeal-Neoplasms

In the presence of 3-isobutyl-l-methylxanthine, VIP produced a dose-related (3 X 10(-9)-10(-7) M) increase (8-fold) in cAMP production in isolated HEp-2 cells incubated at 15 degrees C in KRP buffer. Among the peptides structurally related to VIP, including secretin (10(-7) M), pancreatic glucagon (10(-6) M), PHI, somatostatin-14 (10(-6) M), hpGRF (10(-8)-4 X 10(-6) M), GIP (2 X 10(-7) M), only PHI (3 X 10(-7) M and above) is able to activate the cAMP-generating system in HEp-2 cells, but at 10(2) times lower potency. Under the same conditions, histamine (10(-3) M) was also ineffective, while PGE2 (10(-7)-10(-4) M) increased (4-fold) basal cAMP levels in HEp-2 cells. The VIP effect is related to the interaction of the peptide on VIP recognition sites (125I-VIP-binding capacity), coupled to the membrane-bound adenylate cyclase. The results indicate that the transformed laryngeal cell line HEp-2 possesses a receptor-cAMP system preferentially activated by VIP (relative potencies: VIP greater than PHI much greater than other peptides of the secretin family), and suggest that this neuropeptide could modulate biological functions in normal laryngeal epithelia in man.

Topics: 1-Methyl-3-isobutylxanthine; Cell Line; Cyclic AMP; Humans; Laryngeal Neoplasms; Peptide PHI; Peptides; Receptors, Cell Surface; Receptors, Vasoactive Intestinal Peptide; Vasoactive Intestinal Peptide

Paraganglionic tumors of the larynx are uncommon neoplasms and their secretory products have rarely been elucidated. We saw two patients whose laryngeal paragangliomas were examined with an electron microscope and by the use of immunocytochemical techniques. Both tumors manifested positive immunoreactivity against calcitonin and vasoactive intestinal polypeptide. One of the paragangliomas was immunoreactive against carcinoembryonic antigen and pursued a biologically malignant course. Our observations suggest the coexistence of amines and hormonal polypeptides in cells of paraganglionic tumors and demonstrate the multihormonal nature of these tumors.

Topics: Aged; Calcitonin; Carcinoembryonic Antigen; Female; Humans; Laryngeal Neoplasms; Male; Middle Aged; Paraganglioma; Vasoactive Intestinal Peptide