Hypothalamic–Pituitary–Gonadal Activity in Paradoxical and Psychophysiological Insomnia

Although insomnia is a sex-dimorphic disorder, there is limited knowledge about the association between sex hormones and insomnia. In the present study, we aimed to investigate the level of hypothalamus-pituitary-gonadal (HPG) axis activity in patients with insomnia by measuring serum levels of luteinizing hormone (LH), follicle stimulating hormone (FSH), 17a-Hydroxyprogesterone, testosterone, progesterone, estradiol, dehydroepiandrosterone sulfate, and sex hormone-binding globulin. Numbers of 19 patients; including 13 females (68.4%) with paradox insomnia (32-53 years; 43.2 ± 6.4) and 17 patients; including 8 females (47.1%) with psychophysiological insomnia (14-62 years; 38.4 ± 16.3) were recruited. Seventeen aged-matched normal sleeper consisted of 13 males (26-59 years; 40.7 ± 10) were also recruited as control group. Insomnia was diagnosed by a sleep clinician according to the International Classification of Sleep Disorders-Second Edition criteria and an overnight polysomnography (PSG). A volume of 5 ml of venous blood samples were collected, prepared, and stored at 8 AM under standard condition. Serum levels hormones were measured using enzyme-linked immunosorbent assay kits. Data were analyzed by Chi-square and ANCOVA. Multiple linear regression analysis was used to evaluate the associations between PSG and biochemical parameters. There were no significant differences in all biochemical analyses between two insomnia subgroups (paradoxical and psychophysiological insomnia) and normal sleepers. Testosterone was positively related to maximum pulse transit time (PTT). Moreover, both LH and FSH were positively associated with wake index and diastolic blood pressure. Although there were no significant differences in all HPG's hormones between groups, both LH and FSH were positively associated with wake index and diastolic blood pressure. Moreover, testosterone was positively related to PTT.