Serotonin transporter (5-HTTLPR) genotypes and trinucleotide repeats of androgen receptor exert a combinatorial effect on hormonal milieu in patients with lifelong premature ejaculation

Abstract

Premature ejaculation is one of the most common sexual disorders in men due to uncontrolled modulation of spinal reflexes controlled by cortico-limbic centers in the brain. In this study, we investigate the combinatorial effects of trinucleotide repeats of androgen receptor and allelic variants of the 5-HTTLPR gene on sex steroids, hypophyseal hormones, sexual performance, and premature ejaculation assessment parameters among evidence-based lifelong premature ejaculation subjects. A total of 271 outpatients (age 26.6 ± 1.9) consulting for evidence-based lifelong premature ejaculatory dysfunction were selected in this study. The control group consists of 155 men with normal IELT (>4 min). The study revealed that the subjects who have the highest (≥26) CAG stretches depicted a significantly higher serum oxytocin levels (102.1 pg/ml; n = 126, p < 0.001) compared with the control group (71.2 pg/ml; n = 75, p = <0.001) and patients which have medium (22-25) and short (≤21) CAG stretches (76.63 ng/ml; n = 64, p < 0.001 vs. 77.4 ng/ml; n = 81, p < 0.001). Almost 33 (26.1%) lifelong premature ejaculatory patients had AR variant of longer (≥26) CAG repeats was homozygous for S alleles (SS), 45 (35.7%) was homozygous for L allele (LL), and 48 (38%) had the L/S or S/L genotype of 5-HTTLPR gene. Homozygous (SS) alleles have a significant positive correlation (r = 0.44, p < 0.0001) with the high score of BDI-II (39.1, n = 126, p < 0.001). However, LL alleles have shown a significant positive correlation with PEDT (r = 0.46, p < 0.001) and negative correlation with self-estimated IELT and intercourse satisfaction (r = -0.35, p < 0.001). The innovative study design elaborates that androgen receptor trinucleotide repeats and 5-HTTLPR genotypes have combinatorial impact on hormonal milieu and sexual function regarding evidence-based lifelong premature ejaculatory dysfunction patients.

Keywords: 5-HTTLPR genotypes; Androgen receptor; Lifelong PE; Oxytocin; Testosterone; Tri-nucleotide repeats.