Optimal testosterone level to improve symptoms of hypogonadism without causing dopa-testotoxicosis in male macroprolactinoma

Male prolactinoma treatment by dopamine agonists (DA) restores sexual function. However, excessive DA dose can lead to impulse control disorder.

The aim of this retrospective study was to determine the level of testosterone that eliminates symptoms and provides fertility in male macroprolactinoma, without causing these adverse effects.

Twenty-seven male patients with macroprolactinoma were included. There were 16 macro (≥1-2.8cm), 7 large macro (≥2.9-3.9cm) and 4 giant (≥4cm) adenomas. Prolactin (PRL) and testosterone (T) levels were evaluated. A timeline was created to analyze improvement in symptoms of hypogonadism and infertility. Testosterone levels were compared with age-matched controls.

Mean PRL, basal tumor diameter and shrinkage were 2846±3415ng/mL, 27.2±10.2mm and 63.4%, respectively. Basal T levels were 1.6±1.0ng/mL for patients and 4.4±1.5ng/mL for controls (P<0.001). Mean T level in the asymptomatic period was significantly lower than in controls (3.2±0.4ng/mL vs. 4.4±1.5ng/mL, respectively; P=0.002), while mean PRL was 27.2ng/mL. Fertility was achieved in 6 of the patients seeking fertility, and there was no difference in T level between these patients and controls (3.7±0.8ng/mL and 4.4±1.5ng/mL, respectively; P=0.14); when fertility was achieved, mean PRL was 26.9±23ng/mL.

Patients should be carefully questioned regarding complaints at each consultation, and DA dose should not be increased unnecessarily, to avoid possible serious adverse effects.