Effect of EGF on rat parotid gland secretory function.
The present study reports changes in saliva composition from the rat parotid gland in response to single and repeated administration of epidermal growth factor (EGF). Treatment of rats with EGF (10 micrograms/kg, i.p., twice daily for 3 days) caused an increase in amylase activity in saliva collected from cannulated parotid duct, following stimulation of secretion with pilocarpine, with a corresponding decrease in enzyme activity in the gland. Analysis of parotid gland RNA by reverse transcriptase-PCR generated a single predicted amylase-derived cDNA product of 576 bp. The steady-state levels of mRNA for amylase from EGF-treated parotid total RNA showed a 1.8-fold increase compared to untreated controls. A single dose of EGF (15 min following i.p. injection) elicited an activation of both protein kinase A and protein kinase C activities. While the activation of protein kinase A was still maintained under the chronic EGF regimen, the activity levels of protein kinase C showed down-regulation to untreated control values.
Purushotham
K R
KR
Department of Oral Biology, University of Florida, Gainesville 32610.
Zelles
T
T
Blazsek
J
J
Wang
P
P
Paul
G A
GA
Kerr
M
M
Humphreys-Beher
M G
MG
D000681:Amylases / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000737:chemistry / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D007274:Injections, Intraperitoneal; D051379:Mice; D008969:Molecular Sequence Data; D010306:Parotid Gland / Q000187:drug effects* / Q000378:metabolism; D010862:Pilocarpine / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D011493:Protein Kinase C / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012463:Saliva / Q000187:drug effects / Q000201:enzymology*
D017931:DNA Primers; D018076:DNA, Complementary; D010862:Pilocarpine; D004815:Epidermal Growth Factor; D012313:RNA; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D000681:Amylases