Peptide YY in adolescent athletes with amenorrhea, eumenorrheic athletes and non-athletic controls.
BACKGROUND
Bone mineral density (BMD) is lower in amenorrheic athletes (AA) compared with eumenorrheic athletes (EA). Decreased energy availability and altered levels of appetite regulating hormones (ghrelin and leptin) in AA contribute to hypogonadism, an important cause of low BMD. The role of other nutritionally regulated hormones such as peptide YY (PYY) and adiponectin in mediating gonadal status and bone metabolism remains to be determined.


OBJECTIVE
Our objective was to determine whether PYY and adiponectin are higher in AA compared with EA and contribute to hypogonadism and impaired bone metabolism in AA.


METHODS
We determined PYY and adiponectin in 16 AA, 15 EA and 16 non-athletic controls 12-18 years old, and other nutritionally dependent hormones including ghrelin, leptin and IGF-1. We also measured testosterone, estradiol, PINP and NTX (markers of bone formation and resorption) and BMD.


RESULTS
PYY was higher in AA than EA (111+/-52 vs. 61+/-29 pg/ml, p<0.05), whereas adiponectin did not differ between groups. Although activity scores did not differ, BMI was lower in AA than EA and a larger proportion (62.5% vs. 6.7%) reported disordered eating, indicating lower energy availability. PYY and adiponectin were independent predictors of testosterone in a regression model (p=0.01 and 0.04), but did not predict estradiol. PYY, but not adiponectin, was an independent and negative predictor of PINP (p=0.002) and lumbar bone mineral apparent density Z-scores (p=0.045) in this model.


CONCLUSIONS
High PYY levels (but not adiponectin) differentiate AA from EA, and may be an important factor contributing to low bone density in athletes.
Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
Melissa
M
Russell
Jenna
J
Stark
Shriddha
S
Nayak
Karen K
KK
Miller
David B
DB
Herzog
Anne
A
Klibanski
Madhusmita
M
Misra
D052242:Adiponectin / Q000378:metabolism; D000293:Adolescent; D000568:Amenorrhea / Q000378:metabolism* / Q000503:physiopathology; D001823:Body Composition; D015519:Bone Density; D001842:Bone and Bones / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006801:Humans; D010053:Ovary / Q000378:metabolism; D019894:Peptide YY / Q000378:metabolism*; D012044:Regression Analysis; D013177:Sports / Q000502:physiology*; D013256:Steroids / Q000378:metabolism
D052242:Adiponectin; D013256:Steroids; D019894:Peptide YY