Determinants of IGF1 and GH across the weight spectrum: from anorexia nervosa to obesity.
BACKGROUND
Chronic starvation is characterized by GH resistance, and obesity is characterized by decreased GH secretion. In both extremes, IGF1 levels may be low and androgen levels may be abnormal.


OBJECTIVE
To investigate the determinants of IGF1 and GH across the weight spectrum in women.


METHODS
Cross-sectional study.


METHODS
Clinical research center.


METHODS
In total, 32 women had participated in the study: 11 women with anorexia nervosa (AN), 11 normal-weight women, and 10 obese women of comparable mean age.


METHODS
None.


METHODS
Pooled hourly overnight serum samples assayed for IGF1, GH, estradiol (E(2)), testosterone, SHBG, insulin, free fatty acids, and trunk fat.


RESULTS
Free testosterone was higher in obese women and lower in women with AN than in normal-weight women, and was the only independent (and positive) predictor of IGF1 levels, accounting for 14% of the variability (P=0.032) in the group as a whole. This relationship was stronger when obese women were excluded, with free testosterone accounting for 36% of the variability (P=0.003). Trunk fat accounted for 49% of the variability (P<0.0001) of GH, with an additional 7% of the variability attributable to E(2) (P=0.042) in the group as a whole, but was not a significant determinant of GH secretion when obese women were excluded.


CONCLUSIONS
Free testosterone is a significant determinant of IGF1 levels in women across the body weight spectrum. In contrast, GH secretion is differentially regulated at the extremes of the weight spectrum.
Brick
D J
DJ
Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
Gerweck
A V
AV
Meenaghan
E
E
Lawson
E A
EA
Misra
M
M
Fazeli
P
P
Johnson
W
W
Klibanski
A
A
Miller
K K
KK
D000273:Adipose Tissue / Q000378:metabolism*; D000293:Adolescent; D000856:Anorexia Nervosa / Q000097:blood*; D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology; D003430:Cross-Sectional Studies; D004958:Estradiol / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D019382:Human Growth Hormone / Q000097:blood*; D006801:Humans; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008875:Middle Aged; D009765:Obesity / Q000097:blood*; D011863:Radioimmunoassay; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013739:Testosterone / Q000097:blood
D005230:Fatty Acids, Nonesterified; D007328:Insulin; D012738:Sex Hormone-Binding Globulin; D019382:Human Growth Hormone; D013739:Testosterone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I