THE EFFECT OF DIETARY PROTEIN ON THE CATABOLIC INFLUENCE OF PROGESTERONE*

In 6 comparative studies carried out on 5 healthy subjects, it was shown that the catabolic influence of administered progesterone could be enhanced by substantial dietary protein increments or suppressed by the restriction of protein intake. These effects were observed if the protein content of a diet was increased without alteration in arbohydrate or fat and also when protein was added at the expense of carbohydrate thus maintaining a constant caloric value in comparative diets. Since the digestion and absorption of dietary protein is known to increase the size of the metabolic pool of amino acids, it was concluded that under the conditions of these experiments progesterone was a more effective catabolic agent when this pool was large. It was accordingly suggested that progesterone enhanced the net rate of protein catabolism primarily by accelerating the utilization of amino acids by the liver.