Article

GLP-1 stimulates secretion of macromolecules from airways and relaxes pulmonary artery

Department of Internal Medicine, Philipps University of Marburg, Germany.
The American journal of physiology (Impact Factor: 3.28). 11/1993; 265(4 Pt 1):L374-81.
Source: PubMed

ABSTRACT Recent data revealed the existence of specific receptors for glucagon-like peptide-1(7-36)amide (GLP-1) on rat lung membranes. Utilizing slide-mount autoradiography of fresh frozen lung tissue sections, we have localized binding sites for GLP-1 on mucous glands in the trachea and on vascular smooth muscle of the pulmonary artery. When tracheas were incubated in a modified Ussing chamber, the addition of GLP-1 to the submucosal side increased 35S-sulfate-labeled macromolecule secretion (191 +/- 12% above basal, P < 0.005). The optimal secretory response elicited by GLP-1 was approximately 23% of the maximal secretory response after a maximal acetylcholine stimulation. Other proglucagon-derived peptides such as glucagon, oxyntomodulin, and GLP-2 had no effect. In isolated rings of arteries, GLP-1 (10(-8) to 10(-5) M) induced a dose-dependent and time-reversible relaxation of preconstricted arteries. In a preparation with denuded epithelium, GLP-1 lost its effect. In conclusion, GLP-1 might represent another neuropeptide that acts as neurotransmitter of the peptidergic, nonadrenergic-noncholinergic nervous system that innervates the airways.

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    • "The proglucagon gene encodes peptides with key roles in metabolic activities, such as glucagon, the truncated forms of glucagon-like peptide-1 (GLP-1), i.e., GLP- 1(7–36)amide and GLP-1(7–37), which are powerful stimuli for glucose-dependent insulin secretion (Kreymann et al., 1987) and inhibitors of gastric acid secretion (Schjoldager et al., 1989) and motility (Wettergren et al., 1993), and GLP-2, which may be considered a growth factor acting on epithelial cells of the intestinal mucosa (Drucker et al., 1996). In addition, GLP-1(7–36)amide has effects on peripheral tissues, such as the stimulation of mucus secretion and pulmonary smooth muscle relaxation (Richter et al., 1993), as well as increasing arterial blood pressure and heart rate in rats (Barragán et al., 1994, 1996). This peptide is also considered to be a neuropeptide involved in autonomic and neuroendocrine activities by regulating several functions, such as food intake (Navarro et al., 1996; Tang-Christensen et al., 1996; Turton et al., 1996), water balance (Navarro et al., 1996; Tang-Christensen et al., 1996), body temperature (O'Shea et al., 1996), and the selective release of neurotransmitters (Mora et al., 1992; Calvo et al., 1995b). "
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