Bone mass and the CAG and GGN androgen receptor polymorphisms in young men.
BACKGROUND
To determine whether androgen receptor (AR) CAG (polyglutamine) and GGN (polyglycine) polymorphisms influence bone mineral density (BMD), osteocalcin and free serum testosterone concentration in young men.


RESULTS
Whole body, lumbar spine and femoral bone mineral content (BMC) and BMD, Dual X-ray Absorptiometry (DXA), AR repeat polymorphisms (PCR), osteocalcin and free testosterone (ELISA) were determined in 282 healthy men (28.6+/-7.6 years). Individuals were grouped as CAG short (CAG(S)) if harboring repeat lengths of < or = 21 or CAG long (CAG(L)) if CAG > 21, and GGN was considered short (GGN(S)) or long (GGN(L)) if GGN < or = 23 or > 23. There was an inverse association between logarithm of CAG and GGN length and Ward's Triangle BMC (r = -0.15 and -0.15, P<0.05, age and height adjusted). No associations between CAG or GGN repeat length and regional BMC or BMD were observed after adjusting for age. Whole body and regional BMC and BMD values were similar in men harboring CAG(S), CAG(L), GGN(S) or GGN(L) AR repeat polymorphisms. Men harboring the combination CAG(L)+GGN(L) had 6.3 and 4.4% higher lumbar spine BMC and BMD than men with the haplotype CAG(S)+GGN(S) (both P<0.05). Femoral neck BMD was 4.8% higher in the CAG(S)+GGN(S) compared with the CAG(L)+GGN(S) men (P<0.05). CAG(S), CAG(L), GGN(S), GGN(L) men had similar osteocalcin concentration as well as the four CAG-GGN haplotypes studied.


CONCLUSIONS
AR polymorphisms have an influence on BMC and BMD in healthy adult humans, which cannot be explained through effects in osteoblastic activity.
Guadalupe-Grau
Amelia
A
Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Canary Islands, Spain.
Rodríguez-González
Francisco Germán
FG
Ponce-González
Jesús Gustavo
JG
Dorado
Cecilia
C
Olmedillas
Hugo
H
Fuentes
Teresa
T
Pérez-Gómez
Jorge
J
Sanchís-Moysi
Joaquín
J
Díaz-Chico
Bonifacio Nicolás
BN
Calbet
José A L
JA
D015502:Absorptiometry, Photon; D000328:Adult; D015519:Bone Density / Q000235:genetics*; D006239:Haplotypes; D006801:Humans; D008297:Male; D015675:Osteocalcin / Q000097:blood; D010455:Peptides / Q000235:genetics; D011110:Polymorphism, Genetic / Q000235:genetics*; D011944:Receptors, Androgen / Q000235:genetics*; D013739:Testosterone / Q000097:blood; D055815:Young Adult
C410798:AR protein, human; D010455:Peptides; D011944:Receptors, Androgen; D015675:Osteocalcin; C011080:polyglycine; C097188:polyglutamine; D013739:Testosterone