THE RATIONALE FOR THE USE OF RECOMBINANT HUMAN GROWTH-HORMONE AND INSULIN-LIKE GROWTH-FACTOR-I FOR CATABOLIC CONDITIONS IN HUMANS

Patients with a variety of catabolic illnesses or conditions are subje cted to protein catabolic losses which we attempt to address with trad itional enteral or parenteral nutritional support. Accelerated protein catabolism and energy requirements together with inadequate intake or assimilation of exogenous amino acids are all contributing causes. Ci rculating glucocorticosteroids may play a significant contributing rol e in the redistribution and loss of body protein in acute, and possibl y chronic, catabolic illnesses but such complex metabolic conditions a re not easily studied. Short-term, high-dose glucocorticosteroid admin istration, a model for such protein catabolic condition, increases rat es of whole-body proteolysis, increase amino acid oxidation, and decre ase the effectiveness insulin in suppressing proteolysis. Recombinant human growth hormone (rhGH) administration alone in humans decreases a mino acid oxidation and increases the estimated rate of whole body pro tein synthesis. The exact proteins affected by rhGH and the nutritiona l implications of this, remain to be determined. rhGH when given in co mbination with high-dose glucocorticosteroids offsets the protein cata bolic effects of steroids alone. Thus, rhGH might provide a means to m anipulate protein homeostasis in acute and possibly chronic catabolic conditions. Current data with the use of IGF-I is less clear and will require further investigation to clarify its potential role in such co nditions. Finally, clear clinical utility of adjunctive rhGH and/or rh IGF-I therapy must be demonstrated to justify its wide applicability i n specific clinical settings as a standard care.