AMELIORATION OF THE PROTEIN METABOLIC RESPONSE IN SPERMIDINE-SUPPLEMENTED TRAUMA RATS

Polyamines are biologically active, small, positively charged ubiquito us compounds that play an important role in initiating adaptive change s in cell proliferation, cell growth, and synthesis of proteins and nu cleic acids. The potential for exogenous dietary polyamine to signific antly contribute to whole-body growth and health has not been explored . This study evaluates the efficacy of feeding a liquid diet supplemen ted with 0.05% spermidine in injured rats, Rats traumatized by bilater al femur fracture (n = 12) and pair-fed uninjured controls (n = 12) we re starved for 2 days and then refed for 4 days with a liquid diet con taining 0.05% spermidine or an isonitrogenous control diet. Daily urin e and body weight data were collected. At the end of refeeding, the ra ts were killed, and blood, cerebrospinal fluid (CSF), muscle, and brai n tissue were collected. Spermidine supplementation (0.05%) was found to be tolerated well by the rats and (1) did not affect voluntary food intake by traumatized rats, (2) did not alter the growth rate, (3) in creased protein utilization efficiency, and (4) decreased leucine, iso leucine, and valine levels in plasma and muscle. The profound effect o f trauma on plasma amino acid metabolism seen in rats fed the basal di et was absent in spermidine-supplemented rats. Depletion of plasma glu tamine (GLN) levels due to trauma was significantly less in rats with spermidine supplementation (11% v 33%), indicating a beneficial effect to counteract trauma responses. The results suggest that spermidine s upplementation improves protein utilization efficiency and ameliorates trauma effects on amino acid levels. Copyright (C) 1998 by W.B. Saund ers Company.