TY - JOUR
T1 - Cyclic AMP-dependent amino acid uptake in intestine-. The importance of β-adrenergic agonists
AU - Kinzie, Joseph L.
AU - Grimme, Nancy L.
AU - Alpers, David H.
N1 - Funding Information:
This work, which was supported in part by grants AM-14038 and AM-05280 from the United States Public Health Service, was presented in part at a meeting of the American Society for Clinical Investigation, Atlantic City, N.J.. on Anril 29. 1973.
PY - 1976/12/15
Y1 - 1976/12/15
N2 - Cyclic AMP (cAMP)-dependent stimulation of neutral and dibasic amino acid uptake by intestinal mucosa was investigated by the use of everted intestinal rings, β-adrenergic receptor sites on the mucosal cell itself were implicated, since epinephrine and isoproterenol stimulated uptake in vitro, which was blocked by propranolol. Glucagon, vasopressin and norepinephrine had no effect on tissue cyclic AMP levels or on amino acid uptake but cholera toxin given in vivo increased both parameters tested in vitro. Theophylline and isoproterenol caused an increase in cyclic AMP levels in the villus tip cells, where these drugs also stimulated amino acid uptake. Neither drug increased cAMP in crypt cells. Thus, the cyclic AMP-stimulated uptake of amino acids in vitro is a function of the villus tip cells. Moreover, when metabolic products, such as cAMP, are measured in whole intestinal mucosa, it cannot be assumed that the change is uniform throughout the tissue, but may involve only one type of cell on the intestinal villus.
AB - Cyclic AMP (cAMP)-dependent stimulation of neutral and dibasic amino acid uptake by intestinal mucosa was investigated by the use of everted intestinal rings, β-adrenergic receptor sites on the mucosal cell itself were implicated, since epinephrine and isoproterenol stimulated uptake in vitro, which was blocked by propranolol. Glucagon, vasopressin and norepinephrine had no effect on tissue cyclic AMP levels or on amino acid uptake but cholera toxin given in vivo increased both parameters tested in vitro. Theophylline and isoproterenol caused an increase in cyclic AMP levels in the villus tip cells, where these drugs also stimulated amino acid uptake. Neither drug increased cAMP in crypt cells. Thus, the cyclic AMP-stimulated uptake of amino acids in vitro is a function of the villus tip cells. Moreover, when metabolic products, such as cAMP, are measured in whole intestinal mucosa, it cannot be assumed that the change is uniform throughout the tissue, but may involve only one type of cell on the intestinal villus.
UR - http://www.scopus.com/inward/record.url?scp=0017082198&partnerID=8YFLogxK
U2 - 10.1016/0006-2952(76)90264-1
DO - 10.1016/0006-2952(76)90264-1
M3 - Article
C2 - 12760
AN - SCOPUS:0017082198
VL - 25
SP - 2727
EP - 2731
JO - Biochemical Pharmacology
JF - Biochemical Pharmacology
SN - 0006-2952
IS - 24
ER -