M. Maghnie et al., DIAGNOSING GROWTH-HORMONE DEFICIENCY - THE VALUE OF SHORT-TERM HYPOCALORIC DIET, The Journal of clinical endocrinology and metabolism, 77(5), 1993, pp. 1372-1378
In the attempt to define possible causes of false positive GH deficien
cy, the role of caloric intake on GH determination was explored. The s
erum GH responses to insulin-induced hypoglycemia or arginine were ass
essed before and after 3 days of a hypocaloric diet in 23 prepubertal
children of normal weight, aged 6.7-11.9 yr. Seventeen had short statu
re and a GH response to insulin and arginine below 10 mu g/L, and 6 co
ntrols had normal stature and a GH peak above 10 mu g/L in response to
arginine. After diet, the serum peak GH and the area under the curve
increased in both the patients (P < 0.0005 and P < 0.0005) and the con
trols (P < 0.005 and P < 0.025) with a GH peak greater than 10 mu g/L
in 11 of 17 patients. The patients with a persistent GH response below
10 mu g/L also had lower mean 12-h overnight GH levels (P < 0.0005),
whereas those with a normal GH response after diet had an overnight GH
level greater than 3 mu g/L. In the patients, the mean nighttime GH c
oncentrations correlated with the serum GH peak (r = 0.85; P < 0.005)
and with the area under the curve after the diet (r = 0.65; P < 0.025)
. The diet induced changes in plasma insulin-like growth factor-I, GH-
releasing hormone levels, basal blood sugar and the nadir level obtain
ed during insulin stimulation, total T-3, and rT(3). Height increased
significantly during 1 and 2 yr (P < 0.005) of GH treatment only in pa
tients with a GH response below 10 mu g/L after the diet. These data a
re consistent with the hypothesis that the GH response to stimulation
is strongly calorie dependent and that 3 days of a hypocaloric diet ca
n increase the number and height of GH peaks and the total GH response
s to insulin and arginine. The clear correlation of the GH response to
stimulation after a hypocaloric diet with the mean nighttime GH and a
lso with the growth response to GH treatment indicates that GH deficie
ncy may be overdiagnosed in many children with short stature.