DHEA-S levels in hypopituitaric patients with severe GH deficiency are strongly reduced across lifespan. Comparison with IGF-I levels before and during rhGH replacement

Both IGF-I and DHEA-S undergo an age-related decrease and their decrease co uld be involved in age-related changes in body composition, structure funct ions and metabolism. On the other hand, it is well known that mean IGF-I le vels are clearly reduced in hypopituitaric patients with GH deficiency (GHD ) while data about dehydroepiandrosterone sulfate (DHEA-S) levels in hypopi tuitarism are scanty. We evaluated DHEA-S and IGF-I levels and their relati onship in 90 patients with panhypopituitarism (HYPOPIT) with severe GHD [49 women and 41 men; age, mean+/-SE: 47.9+/-1.49 yr, range: 20-80 yr; BMI: 26 .4+/-0.6 kg/m(2); 21 with childhood-onset (CO) and 69 with adult-onset (AO) HYPOPIT]. DHEA-S and IGF-I levels were also evaluated in 24 HYPOPIT with G HD after 3-month recombinant human GH (rhGH) replacement. Data in HYPOPIT w ere compared with those in a large group of healthy controls (NS, 233 women and 103 men, aged 20-80 yr; all subjects were within +/- 15% of their idea l body weight). In NS both DHEA-S levels and IGF-I were gender-independent while showed a strong, inverse correlation with age (r=-0.6; p<0.001 and r= -0.56; p<0.0001, respectively). Nevertheless, no relationship was found bet ween DHEA-S and IGF-I levels in NS. In HYPOPIT, age-adjusted mean DHEA-S an d IGF-I levels were clearly lower than those in NS (2.3+/-0.4 vs 16.0+/-0.7 mu g/l, p<0.005; 71.1+/-4.5 vs 170+/-4.7 mu g/l, p<0.005). IGF-I levels in CO-HYPOPIT were lower (p<0.01) than those in AO-HYPOPIT (49.6+/-4.8 vs 77. 0+/-5.4 mu g/l), while DHEA-S levels were similar in both subgroups (2.6+/- 0.7 vs 2.3+/-0.4 mu g/l). In HYPOPIT both DHEA-S and IGF-I were independent of age and gender while there was a trend toward a positive association be tween each other (r=0.45; p<0.003). Analyzing individual levels in HYPOPIT with respect to age-adjusted normal ranges, IGF-I levels were below normal in 84, 62 and 0% between 20-40, 40-60 and 60-80 yr, respectively. On the ot her hand, DHEA-S levels were below normal in 84, 86 and 67% between 20-40, 40-60 and 60-80, respectively. In HYPOPIT rhGH treatment strikingly increas ed IGF-I levels (150+/-3.2 vs 85.3+/-4.1 mu g/l, p<0.005) while did not mod ify DHEA-S levels (1.7+/-0.2 vs 1.6+/-0.2 mu g/l). In conclusion, our resul ts demonstrate that DHEA-S and IGF-I are negatively and independently assoc iated to age in physiological conditions but not in hypopituitaric patients in whom both are strikingly reduced. Both DHEA-S and IGF-I levels in HYPOP IT show some overlap with those in normal subjects; thus the assay of these parameters is not diagnostic for hypopituitarism. DHEA-S reduction in HYPO PIT does not depend on IGF-I as indicated also by evidence that GH replacem ent restores IGF-I but does not modify DHEA-S levels. (C) 2000, Editrice Ku rtis.