Effect of ?-methylnorepinephrine, an ?2-adrenergic agonist, on jejunal absorption in neurally intact conscious dog

1993 ◽  
Vol 38 (9) ◽  
pp. 1645-1650 ◽  
Author(s):  
Sharon M. Herkes ◽  
C. Daniel Smith ◽  
Lawrence P. Prabhakar ◽  
Sidney F. Phillips ◽  
Michael G. Sarr
Author(s):  
L.S. Cutler

Many studies previously have shown that the B-adrenergic agonist isoproterenol and the a-adrenergic agonist norepinephrine will stimulate secretion by the adult rat submandibular (SMG) and parotid glands. Recent data from several laboratories indicates that adrenergic agonists bind to specific receptors on the secretory cell surface and stimulate membrane associated adenylate cyclase activity which generates cyclic AMP. The production of cyclic AMP apparently initiates a cascade of events which culminates in exocytosis. During recent studies in our laboratory it was observed that the adenylate cyclase activity in plasma membrane fractions derived from the prenatal and early neonatal rat submandibular gland was retractile to stimulation by isoproterenol but was stimulated by norepinephrine. In addition, in vitro secretion studies indicated that these prenatal and neonatal glands would not secrete peroxidase in response to isoproterenol but would secrete in response to norepinephrine. In contrast to these in vitro observations, it has been shown that the injection of isoproterenol into the living newborn rat results in secretion of peroxidase by the SMG (1).


1986 ◽  
Vol 113 (4) ◽  
pp. 471-478 ◽  
Author(s):  
R. J. Kemppainen ◽  
J. L. Sartin

Abstract. In order to examine regulation of pituitary intermediate lobe secretion, plasma immunoreactive (i)ACTH, cortisol, and α-MSH responses to iv bolus injections of CRF, quipazine maleate (serotonin agonist), isoproterenol (β-adrenergic agonist) or haloperidol (dopamine antagonist) were determined in conscious, unrestrained dogs. Endocrine responses to these test substances were also determined in dogs pre-treated with dexamethasone. Administration of one or more doses of each test substance resulted in significant elevations in plasma iACTH and cortisol concentrations. Only haloperidol injection caused significant increases in plasma iα-MSH. Following dexamethasone pre-treatment, plasma iACTH and cortisol increases in response to all test substances were considerably reduced or abolished. Dexamethasone did not alter baseline or haloperidol-stimulated plasma ia-MSH concentrations. However, infusion of bromocriptine mesylate (dopamine agonist) in combination with dexamethasone pre-treatment reduced the plasma iα-MSH response to haloperidol. We conclude that a dopaminergic pathway is important in the in vivo regulation of pituitary intermediate lobe activity in dogs.


Diabetes ◽  
1980 ◽  
Vol 29 (9) ◽  
pp. 702-709 ◽  
Author(s):  
M. P. Diamond ◽  
R. C. Rollings ◽  
L. Erlendson ◽  
P. E. Williams ◽  
W. W. Lacy ◽  
...  

Diabetes ◽  
1982 ◽  
Vol 31 (10) ◽  
pp. 917-922 ◽  
Author(s):  
A. D. Cherrington ◽  
M. P. Diamond ◽  
D. R. Green ◽  
P. E. Williams

Diabetes ◽  
1986 ◽  
Vol 35 (7) ◽  
pp. 776-784 ◽  
Author(s):  
K. E. Steiner ◽  
S. M. Mouton ◽  
P. E. Williams ◽  
W. W. Lacy ◽  
A. D. Cherrington

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