The effect of chronic treatment with GH on gonadal function in men with isolated GH deficiency

Eleven adult males, previously submitted to neurosurgery because of a pituitary lesion (three with craniopharyngioma, three with clinically non-functioning adenoma and five with macroprolactinoma) were treated with recombinant GH for 12 months after the diagnosis of GH deficiency was made. Circulating FSH, LH, prolactin, testosterone, 17 beta-estradiol (E-2) dehyroepiandrosterone (DHEA-S), androstenedione, 17-OH-progesterone (17OHP), IGF-I, and steroid hormone-binding protein (SHBG) levels were assayed before and after CG test at study entry and 6 and 12 months after GH treatment. A significant increase in plasma IGF-I levels was obtained after 6 and 12 months of GH treatment. Ln addition, CG-stirnulated, but not baseline, testosterone levels showed a significant increase after 6 and 12 months of GH treatment when compared with study entry (9.6+/-0.5 and 4.9+/-0.5 vs 7.9+/-0.5 ng/ml P<0.05). Baseline, but not CG-stimulated, serum 17OHP levels were significantly increased only after 12 months of GH treatment (1.7+/-0.1 vs 1.4+/-0.1 ng/ml; P<0.05), No significant difference was found as far as both basal and CG-stimulated E-2 androstenedione, DHEA-S and SHBG were concerned. With regards to the semen analysis, only seminal plasma volume was significantly increased after 12 months of GH treatment (2.9+/-0.3 vs 1.7+/-0.3 ml; P<0.05). No significant change in sperm count, motility and abnormal forms was observed. These data show that GPI treatment displays a clear-cut effect upon Leydig cell function and increases the production of seminal plasma volume in fertile adult males with isolated GH deficiency