The effect of in utero protein malnutrition and subsequent renutrition on rat saliva and some salivary enzymes

Effects of protein deficiency and diet consistency on the parotid gland and parotid saliva of rats

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)

Effect of a long-term change from a mixed to a lactovegetarian diet on human saliva

The effects of this long-term dietary change on secretion rate, buffer capacity, concentration of sodium and potassium and amylase activity of stimulated parotid and whole saliva was studied in 20 healthy, normal-weight, non-smoking omnivores. Salivary counts of mutans streptococci and lactobacilli were also made. Dietary surveys were carried out and saliva samples collected before (baseline) and 3, 6 and 12 months after the dietary change as well as 3 yr after the end of the lactovegetarian diet period. The dietary data showed an increase in the consumption of fruits, vegetables and dairy products and a decrease in meat, fish, eggs, sweets and biscuits. These changes led to an increased intake of carbohydrates, fibre and water. After 12 months on the vegetarian diet, the secretion rate, buffer capacity and sodium concentration of whole saliva and the secretion rate of parotid saliva had increased significantly. At the 3-yr follow-up, the buffer capacity and sodium concentration were still elevated, while the secretion rate had almost returned to the baseline values. The potassium content of whole saliva showed a tendency to increase during the vegetarian diet period, but had decreased again at the 3-yr follow-up.

Effect of protein malnutrition on the composition of submandibular glands of aged rats

Fifty 22-month-old male Sprague-Dawley rats were fed for 8 weeks ad libitum with either a 20% protein diet (control) or a 5% protein diet (protein malnourished group). Submandibular glands were removed, weighed and homogenate prepared. After the low protein diet, there was a slight but significant decrease in body weight, glandular content of total protein (mg/g tissue), kallikrein activity/mg protein and glutamine-rich peptide. In contrast, the gland weight, DNA and mucin content were not changed by feeding a low protein diet. Thus in aged rats submandibular glands are only modestly affected by protein malnutrition and the effects on gland-specific proteins vary.