Journal of Dental Research, Vol 69, 60-66, Copyright © 1990 by International & American Associations for Dental Research Online Journals
Changes in protein secretion by rat submandibular glands in response to isoproterenol, alpha-methylnoradrenaline, and clonidine during post-natal development
E. Tanaka, T. Habu, A. Letic-Gavrilovic and K. Abe
First Department of Prosthodontics, Fukuoka Dental College, Japan.
We studied developmental changes in salivary volumes and proteins secreted
by the submandibular glands of male rats at weekly intervals from two to
ten weeks of age in response to the beta 1-, alpha 1-, and alpha
2-adrenoceptor agonists, isoproterenol (IPR), alpha-methylnoradrenaline
(alpha-mNA), and clonidine (Clonid). The types of proteins in saliva
samples were determined and compared by isoelectric-focusing
electrophoresis with the Phast system in both the gradient pH -3.5-to-5 and
pH-3.5-to-9 gels by means of silver staining. Salivary volume and protein
concentration in saliva samples elicited by IPR and alpha-mNA were
positively related to the weight of the submandibular glands up to six or
seven weeks of age, whereas in saliva elicited by Clonid, no relation was
found in the protein concentration [corrected]. The isoelectric-focusing
electrophoretic patterns of proteins secreted by the glands in response to
three stimuli were different from each other during post-natal development.
Within one stimulation, differences were also observed at two and three
weeks of age for Clonid, and from seven weeks of age for the three stimuli,
respectively. The alpha-type proteins, but not the beta-type proteins, were
very similar to those in extracts from glands of rats at seven weeks of
age. Almost all of the alpha-type proteins, but not the beta-type proteins,
reacted with antibodies to two proteases. We conclude that functional
maturation precedes morphological maturation in the submandibular glands of
rats.
