IGF1 and acromegaly: Serum GH levels in the NGRD group were significantly different from those in the acromegaly group (P<0.001) and GHD group (P<0.01) (Figure 1A), and serum IGF-I levels were also different in the acromegaly group (P<0.001) and GHD group (P<0.001) (Figure 1B).