The behavior of alanin in metabolism

Injection of 20 grams of i-alanin in a completely phlorhizinized dog resulted in the elimination of “extra sugar” in the urine to an amount equalling 18.8 grams, or 93 per cent. of that theoretically possible. Although i-alanin is almost completely convertible into dextrose, preliminary respiration experiments indicate that it does not spare fat metabolism as effectually as does dextrose itself. This may be due to heat loss in the breaking down of alanin into simpler molecules (formic aldehyde?) and heat absorption in its construction into dextrose. A similar reasoning would serve to explain Rubner's “specific dynamic action” of protein.