AJP - Gastrointestinal and Liver Physiology, Vol 257, Issue 4 561-G569, Copyright © 1989 by American Physiological Society
Vasoactive intestinal peptide and its receptors in fetuses with cystic fibrosis
E. Chastre, W. Bawab, C. Faure, S. Emami, F. Muller, A. Boue and C. Gespach
Institut National de la Sante et de la Recherche Medicale U.55, Hopital Saint-Antoine, Paris, France.
Fetuses were investigated to establish whether vasoactive intestinal
peptide (VIP) and its receptors are involved in the basic biochemical
defect causing cystic fibrosis (CF). The intestine was used as a target for
the disease and the liver as control. The immunoreactive and biologically
active VIP contents of the colon and lower part of the small intestine were
1.5-2.5 times higher in CF fetuses than in controls. In control and CF
intestinal mucosa, there was no change in the Scatchard parameters of the
125I-labeled VIP binding sites (Kd = 4.7-6.1 X 10(-11) M; Bmax = 268-280
fmol/mg protein for the high-affinity sites), in the two molecular
components constituting the cross-linked 125I-VIP binding (Mr = 66,000 and
30,000), or in the pharmacological properties and functional
characteristics of the VIP receptors activating the G proteins-adenylate
cyclase system (Ka = 0.7 X 10(-9) M VIP). Similar results were obtained in
liver. These findings suggest that neither VIP nor its receptors are
involved in CF intestine. The possible involvement of other effectors
related to the VIP pathway in CF intestine, including the release of VIP
and adenosine 3',5'-cyclic monophosphate signal-transduction cascade, are
presented.
