Normal IGF-I and enhanced IGFBP-3 response to very low rhGH dose in patients with dilated cardiomyopathy

Well-nourished patients with dilated cardiomyopathy (DCM) show slight reduc tion of mean basal IGF-I levels which, however, display a response to a rhG H dose as low as 5.0 mu g/kg/day similar to that of age-matched control sub jects ICS). To further investigate peripheral GH sensitivity, we studied th e IGF-I and IGFBP-8 responses to 4-day sc 2.5 mu g/kg/day rhGH administrati on, the lowest effective dose able to increase IGF-I levels in normal subje cts, in 10 DCM patients [age (mean+/-SE): 57.6+/-1.0 yr, body mass index (B MI): 24.0+/-1.2 kg/m(2), left ventricular ejection fraction: 26.2+/-3.2%, N YHA (New York Heart Association): I/0, II/4, III/4, IV/2] and in 9 age-matc hed healthy CS (age: 55.3+/-1.2 yr, BMI: 23.7+/-1.8 kg/m(2)). Basal IGF-I l evels in DCM were lower though not significantly than those in CS (147.7+/- 9.8 vs 174.7+/-17.0 mu g/l). Basal IGFBP-3 levels in DCM were similar to th ose in CS (3.1+/-0.3 vs 2.7+/-0.2 mg/l). In CS LF-day rhGH increased IGF-I levels (222.4+/-14.9 mu g/l; p<0.01 vs baseline) but did not modify IGFBP-3 levels (3.0+/-0.2 mg/l). In DCM IGF-I levels were increased by 4-day rhGH administration (175.7+/-11.0 mu g/l; p<0.05 vs baseline) with a similar per cent extent than in CS. On the other hand, in DCM, but not in CS, 4-day rhG H significantly increased IGFBP-3 levels (3.5+/-0.3 mg/l; p<0.05 vs baselin e). Therefore, in conclusion, testing with the lowest effective rhGH dose f urther suggest that peripheral GH sensitivity in well-nourished DCM is pres erved. On the other hand, DCM patients show enhanced IGFBP-3 sensitivity to stimulation by rhGH. (J. Endocrinol. Invest. 23: 520-525, 2000) (C) 2000, Editrice Kurtis.