Lower visceral and subcutaneous but higher intermuscular adipose tissue depots in patients with growth hormone and insulin-like growth factor I excess due to acromegaly.
BACKGROUND
GH and IGF-I are important regulators of metabolism and body composition. In acromegaly, a state of GH and IGF-I excess, the lipolytic and insulin antagonistic effects of GH may alter adipose tissue (AT) distribution.


OBJECTIVE
Our objective was to test the hypothesis that in acromegaly whole-body AT mass is less and to examine for the first time the relationship between GH/IGF-I excess and intermuscular AT (IMAT), an AT depot associated with insulin resistance in other populations.


METHODS
We conducted a cross-sectional study in 24 adults with active acromegaly compared with predicted models developed in 315 healthy non-acromegaly subjects.


METHODS
Mass of AT in the visceral AT (VAT), sc AT (SAT), and IMAT compartments from whole-body magnetic resonance imaging and serum levels of GH, IGF-I, insulin, and glucose were measured.


RESULTS
VAT and SAT were less in active acromegaly (P < 0.0001); these were 68.2 +/- 27% and 79.5 +/- 15% of predicted values, respectively. By contrast, IMAT was greater (P = 0.0052) by 185.6 +/- 84% of predicted. VAT/trunk AT ratios were inversely related to IGF-I levels (r = 0.544; P = 0.0054). Acromegaly subjects were insulin resistant.


CONCLUSIONS
VAT and SAT, most markedly VAT, are less in acromegaly. The proportion of trunk AT that is VAT is less with greater disease activity. IMAT is greater in acromegaly, a novel finding, which suggests that increased AT in muscle could be associated with GH-induced insulin resistance. These findings have implications for understanding the role of GH in body composition and metabolic risk in acromegaly and other clinical settings of GH use.
Freda
Pamela U
PU
Department of Medicine, Columbia University, College of Physicians and Surgeons, 650 West 168th Street, New York, NY 10032, USA. puf1@columbia.edu
Shen
Wei
W
Heymsfield
Steven B
SB
Reyes-Vidal
Carlos M
CM
Geer
Eliza B
EB
Bruce
Jeffrey N
JN
Gallagher
Dympna
D
D000172:Acromegaly / Q000378:metabolism / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D050218:Body Fat Distribution; D003430:Cross-Sectional Studies; D005260:Female; D013006:Growth Hormone / Q000378:metabolism*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D050152:Intra-Abdominal Fat / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D008962:Models, Theoretical; D018482:Muscle, Skeletal / Q000473:pathology*; D009929:Organ Size; D050151:Subcutaneous Fat / Q000473:pathology*
D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone