Effect of rhgh and rhigf-i treatment on protein utilization in
elderly women.
Butterfield, G. E., J. Thompson, M. J. Rennie, R. Marcus, R. L. Hintz,
and A. R. Hoffman.
GRECC and Medical Science, Veterans Affairs Health Care System,
Palo Alto, California, 94304, Departments of Medicine and Pediatrics,
Stanford University, 94305 and University of Dundee, Dundee,
Scotland, DD1, 4HN, UK
APStracts 3:0187E, 1996.
To assess the effect of recombinant human growth hormone (rhGH) and
recombinant human insulin-like growth factor-I (rhIGF-I) on protein
utilization, 14 women, 66 to 82 y, were invited to participate in
studies of nitrogen balance (n=14), whole body protein turnover
(n=14), and muscle protein synthesis (n = 8). They were studied both
one week before and during the last week of a one month regimen of
either 0.025 mg rhGH/kg once daily or rhIGF-I at 0.015 (low), 0.030
(mid) or 0.060 (high) mg/kg twice daily, to which they had been
randomly assigned. Nitrogen balance increased significantly after 1
week of treatment in all groups (p<0.05). After 1 month, the
magnitude of this effect had diminished by 50% in the rhGH group, but
remained elevated throughout the treatment period with all doses of
rhIGF-I. Both protein synthesis and breakdown, measured by a primed
constant infusion of 15-N-glycine, were significantly increased with
rhGH (9% and 8%, respectively), low dose rhIGF-I (4.5% and 4%), and
high dose rhIGF-I (18% and 17%). Net synthesis was significantly
increased with rhGH (48%) and high and mid dose rhIGF-I (27% and 196%
respectively). Muscle protein synthesis as measured by incorporation
of [1-13C]-leucine increased significantly with rhGH (50%) and the
mid (67%) and high (57%) doses of rhIGF-I. These data show that whole
body and muscle protein synthesis are responsive to growth factor
stimulation in elderly women.
Received 23 January 1996; accepted in final form 19 August 1996.
APS Manuscript Number E53-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996