[Influence of hypoproteinemia on the development of skull, mandible and teeth of the rats--metrical studies].

The amounts of plasma protein in eight groups of rats, A-H, was controlled by diet and a daily study was undertaken to investigate the effect that varying amounts of plasma protein have on body weight, the growth and development of body length, growth of the skull and mandible and development of the teeth. The following conclusions were obtained. 1. It was possible to keep the amount of plasma protein constant in each group by using a specially prepared diet containing differing amounts of casein. Also, when the rats with hypoproteinemia, due to a non-casein diet, were given food containing 24.5% casein, it was found that their plasma protein levels easily and quickly returned to normal. 2. Weight: Counting the first day of the experiment as 100, growth for group A (given a 24.5% casein diet) had reached 281.7% by the fifteenth week, whereas group H (fed a non-casein diet) reached a growth of only 48.5%--below half of day one of the experiment. On the other hand, each group which started out with a non-casein diet and later changed to a 24.5% casein diet recovered very quickly, but not to the extent of group A by the fifteenth week. Body length for all experimental groups increased from the first day to the third week, after which there was a tendency to approximate the body weight. 3. Effect of hypoproteinemia on skull growth: Growth was small for groups B and C whose plasma protein amounts were kept constant. Hardly any growth was seen in groups D and H. Groups E, F and G, whose plasma protein levels were restored, showed a high growth ratio after their diet was changed. Growth of the mandible showed a similar pattern. 4. A comparison of measurements for different parts of the skull indicated different patterns of growth and development for the upper and lower parts. For the upper part, the least growth was in the center followed by the rear area with the largest growth for the nasal bone at the front. The greatest growth ratio in the lower part of the skull was seen in splenoid and occipital bone lengths at the rear followed by the front area and central area. Growth of angular process length of mandible showed a very high growth ratio. 5. The amount of growth for each part of the skull from the largest to the smallest was found to be in the same order for both the upper and lower parts: the front, center and rear.(ABSTRACT TRUNCATED AT 400 WORDS)