ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2008) 16 P627

Effects of testosterone undecanoate (TU) administered alone or in combination with letrozole or dutasteride in female to male transexuals (FtM)

Maria Cristina Meriggiola1, Francesca Armillotta1, Paola Altieri1, Antonietta Costantino1, Silvia Cerpolini1, Marta Berra1, Anna Myriam Perrone1, Farid Saad2 & Giuseppe Pelusi1

1Center for Sexual Health, Ob Gyn Department, University of Bologna, Bologna, Italy; 2Bayer-Schering Pharma, Men’s Healthcare, Berlin, Germany.

TU is an effective option for androgen replacement in FtM subjects, but long-term physiological effects and the significance of T and its metabolites dihydrotestosterone (DHT) and estradiol (E) on physiological functions are unclear. The aim of our study was to investigate the effects of long-term TU treatment on bone metabolism, body composition and lipid profile in FtM subjects and to evaluate the relationship between the observed effects and circulating levels of T, E and DHT. This was a 1-year, randomised treatment, open label, uncontrolled safety study. Ovariectomized FtM were randomly assigned to receive 1000 mg TU injection at week 0, 6, 18, 30, 42 and 54 alone (TU-alone, n=5) or in combination with letrozole 2.5 mg, orally (TU+L, n=5) or dutasteride 5 mg, orally (TU+D, n=5). The Ethics Committee of the S Orsola Hospital approved the study. Outcome parameters included measurement of reproductive hormones, bone metabolism, body composition and lipid profile. Hormones at baseline and at week 54, in group TU-alone, TU+D and TU+L respectively were:

Total T (nmol/l) 7.9+6.0 and 13.6+2.6; 7.1+6.3 and 18.4+4.6§; 4.8+4.8 and 18.2+4.2§; E (pmol/l) 64.4+43.4 and 89.6+36.3; 41.4+19.4 and 76.0+47.4; 37.8+23.1 and 18.0+0.0*; DHT (nmol/l) 1.3+1.2 and 2.2+0.9; 1.0+0.7 and 0.4+0.1*; 0.9+0.7 and 2.7+1.3; *=P<0.05% change versus TU-alone; §=P<0.05 versus baseline. TU-alone and TU +D treatments were successful in terms of hormone adjustment, did not result in any adverse effects and were well tolerated. BMD decreased by an average of 0.9 g/cm in the TU +L group and the addition of dutasteride resulted in a failure to gain lean mass.

Conclusions: This study confirms that TU is a successful and safe treatment for FtM subjects. Results indicate that E has an important role in bone metabolism and that DHT might play a role in muscle development.