Central body fat changes in men affected by post-surgical hypogonadotropic hypogonadism undergoing testosterone replacement therapy are modulated by androgen receptor CAG polymorphism.
OBJECTIVE
Little is known about the effect of androgen receptor (AR) gene CAG repeat polymorphism in conditioning body composition changes after testosterone replacement therapy (TRT). In this study, we aimed to clarify this aspect by focussing our attention on male post-surgical hypogonadotropic hypogonadism, a condition often associated with partial or total hypopituitarism.


RESULTS
Fourteen men affected by post-surgical hypogonadotropic hypogonadism and undergoing several replacement hormone therapies were evaluated before and after TRT. Dual-energy X-ray absorptiometry (DEXA)-derived body composition measurements, pituitary-dependent hormones and AR gene CAG repeat polymorphism were considered. While testosterone and insulin-like growth factor-1 (IGF-1) levels increased after TRT, cortisol concentration decreased. No anthropometric or body composition parameters varied significantly, except for abdominal fat decrease. The number of CAG triplets was positively and significantly correlated with this abdominal fat decrease, while the opposite occurred between the latter and Δ-testosterone. No correlation of IGF-1 or cortisol variation (Δ-) with Δ-abdominal fat was found. At multiple linear regression, after correction for Δ-testosterone, the positive association between CAG triplet number and abdominal fat change was confirmed.


CONCLUSIONS
In male post-surgical hypogonadotropic hypogonadism, shorter length of AR CAG repeat tract is independently associated with a more marked decrease of abdominal fat after TRT.
Division of Endocrinology, Department of Clinical and Molecular Sciences, Umberto I Hospital, Polytechnic University of Marche, Ancona, Italy.
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Tirabassi
Division of Endocrinology, Department of Clinical and Molecular Sciences, Umberto I Hospital, Polytechnic University of Marche, Ancona, Italy.
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delli Muti
Division of Endocrinology, Department of Clinical and Molecular Sciences, Umberto I Hospital, Polytechnic University of Marche, Ancona, Italy.
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Buldreghini
Andrology, Pathophysiology of Reproduction and Endocrine Diagnosis Unit, Policlinic Umberto I, University of Rome 'La Sapienza', Rome, Italy.
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Lenzi
Division of Endocrinology, Department of Clinical and Molecular Sciences, Umberto I Hospital, Polytechnic University of Marche, Ancona, Italy. Electronic address: g.balercia@ospedaliriuniti.marche.it.
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Balercia
D050153:Abdominal Fat / Q000502:physiology*; D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition; D001835:Body Weight; D020249:Hormone Replacement Therapy; D006801:Humans; D007006:Hypogonadism / Q000188:drug therapy* / Q000473:pathology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D011110:Polymorphism, Genetic; D011183:Postoperative Complications / Q000188:drug therapy* / Q000473:pathology*; D011944:Receptors, Androgen / Q000235:genetics* / Q000378:metabolism; D012189:Retrospective Studies; D013739:Testosterone / Q000627:therapeutic use*; D055105:Waist Circumference
C410798:AR protein, human; D011944:Receptors, Androgen; D013739:Testosterone; D007334:Insulin-Like Growth Factor I
Androgen receptor; Body composition; Dual-energy X-ray absorptiometry; Hypogonadotropic hypogonadism; Hypopituitarism; Testosterone