AJP - Regulatory, Integrative and Comparative Physiology, Vol 258, Issue 6 1320-R1326, Copyright © 1990 by American Physiological Society
Cyclic nucleotide responses in control and cystic fibrosis labial glands
B. J. Allan, K. T. Izutsu, B. W. Ramsey, M. M. Schubert, W. Y. Ensign and E. L. Truelove
Department of Oral Biology, School of Dentistry, University of Washington, Seattle 98195.
Adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic
monophosphate (cGMP) levels were measured in labial gland slices from
controls and patients with cystic fibrosis (CF). Incubation in vitro with
10 microM epinephrine, 50 microM isoproterenol, or 10 microM carbachol
increased cAMP levels by 2.3-fold, 3.1-fold, and 1.8-fold, respectively, in
control glands and by similar amounts in CF glands. The only statistically
significant CF-related difference was a decreased response to
isoproterenol. Addition of MIX (3-isobutyl-1-methylxanthine) increased cAMP
levels in control and CF glands by an order of magnitude under all
conditions but did not eliminate the CF-related decrease in cAMP level
obtained with isoproterenol. cGMP levels were measured only in the presence
of MIX. Incubation with carbachol nearly doubled cGMP levels in control and
CF glands but only the control gland response approached statistical
significance (P = 0.06). cGMP levels in CF glands were nearly threefold
greater than those in control glands, and disease-related differences
obtained in the presence of carbachol and isoproterenol were statistically
significant.
