The Salivary Glands in Lysine-deficient Young Rats

¹ National Institute of Dental Research, National Institutes of Health, Public Health Service, U.S. Department of Health, Education and Welfare, Bethesda, Maryland

1. A study was made of young white rats given a lysine-deficient, zein-base diet, as well as a lysine-limited diet containing autoclaved skim-milk powder as the source of protein.

2. Impaired growth on this diet was corrected by a lysine supplement. Dental caries resulted on the skim-milk-powder diet. This diet was less cariogenic with a lysine supplement.

3. Salivary gland and tongue development on both gross and cellular levels was impaired by severe lysine deficiency, but not by the lysine-limited diet. Lysine deficiency produced no other distinctive gross or microscopic changes in these organs.

4. No changes were found in the total nitrogen, protein, tyrosine, and "tryptophan" content of the saliva due to inadequate lysine.

5. Although the mortality rate in 60-day lysine-deficient rats was increased, the incidence of "spontaneous" lesions, mainly pneumonitis, was no greater and apparently not a factor.

6. Repletion of animals with 1 per cent lysine daily after being subject to a deficient diet for 30 days produced no gross or microscopic changes in the salivary glands or tongue.