Gluconeogenesis in Very Low Birth Weight Infants Who Are Receiving Nutrition By Intravenous Infusion

RATIONALE: Very low birth weight infants have problems maintaining normal blood sugar levels. Gluconeogenesis is the production of sugar from amino acids and fats. The best combination of amino acids, fat, and sugar to help very low birth weigh infants maintain normal blood sugar levels is not yet known. PURPOSE: Clinical trial to study how very low birth weight infants break down amino acids, fat, and sugar given by intravenous infusion, and the effect of different combinations of nutrients on the infants' ability to maintain normal blood sugar levels.