Journal of Dental Research, Vol 74, 1444-1452, Copyright © 1995 by International & American Associations for Dental Research Online Journals
Effects of protein deficiency and diet consistency on the parotid gland and parotid saliva of rats
D. A. Johnson, H. Lopez and J. M. Navia
Department of Community Dentistry, University of Texas Health Science Center at San Antonio 78284-7917, USA.
Protein deficiency results in an increased susceptibility to dental caries,
suggesting that oral host-defense properties are compromised. An important
component of oral host defense is salivary gland function, which is
affected by both protein deficiency and diet consistency. This study
describes the effects on rat parotid gland growth and secretory function
induced by feeding rats diets of normal (20%) or moderately low (7%)
protein content, provided in either a powdered or solid form. In addition,
since protein deficiency may result in a secondary zinc deficiency which,
in turn, may affect salivary gland function, the effects of these diets on
liver zinc concentration were also measured. From 22 to 47 days of age,
rats (18/group) were fed the following diets: normal protein, powdered;
normal protein, solid; low protein, powdered; and low protein, solid. With
each diet consistency, liver zinc was higher for the normal protein group.
Within each protein level, liver zinc was higher for the solid diet. This
latter observation suggests that food mastication and the resultant
stimulation of salivary gland function may also play a role in zinc
metabolism. With the normal-protein diet, parotid gland weight was higher
for the solid diet; with the low-protein diet, parotid gland weight was
similar for both consistencies and did not differ from that of the group
fed the "normal protein, powdered" diet. For both consistencies, parotid
saliva protein concentration was greater for malnourished rats.(ABSTRACT
TRUNCATED AT 250 WORDS)
