Nutritional studies of the roles of dietary protein levels and umami in the preference response to sodium chloride for experimental animals.

Previously we found that appetite or preference for sodium chloride depends not only on a genetic factor, but also on the nutritional status, i.e., dietary protein levels. To determine whether all kinds of protein had reducing effects on sodium chloride intake, the effect of dietary protein source on appetite or preference for sodium chloride was studied. It was found that the effect depended not only on protein levels, but also on the protein sources, i.e., amino acid patterns of diets. On the other hand, the turnover time of gustatory taste bud cells was measured by the pulse-labeled method using 3H-thymidine. It was found that the turnover time of gustatory cells in the taste buds of rats fed a low-protein diet was longer than in rats fed a high-protein diet. This suggested that some reduction of receptor functions may occur with low-protein diet. It was found that the dietary protein levels and umami also modified appetite or preference for alcohol solutions.