Testicular function in postpubertal patients with growth hormone deficiency: A prospective controlled study

Abstract

Background: We have previously shown that treatment with recombinant human growth hormone (GH) influences testicular growth in children with GH deficiency (GHD) and have suggested that GH plays a role in testicular growth in childhood. Little evidence is available on testicular function in post-pubertal GHD patients.

Objective: This prospective controlled study was undertaken to evaluate testicular function in patients with GHD.

Patients and methods: Post-pubertal patients with non-syndromic GHD over the age of 16 years were enrolled. Each patient underwent to the assessment of serum levels of gonadotropins and total testosterone (TT), conventional sperm parameters, and testicular volume (TV) measured by ultrasound examination. Age-matched healthy subjects served as controls. Patients with disorders capable of interfering with testicular function were excluded.

Results: 26 patients with GHD and 25 age-matched post-pubertal controls were enrolled. They did not differ in serum luteinizing hormone, follicle-stimulating hormone, and TT levels. However, GHD patients had lower semen volume, total sperm count, progressive motility, and total motility values, and a higher prevalence of oligozoospermia compared to controls. No difference was found in sperm concentration and normal morphology. Importantly, GHD patients had lower TV, and a higher prevalence of testicular hypotrophy.

Conclusion: This is the first evidence of mildly impaired sperm parameters and TV in GHD patients compared to healthy controls. The integrity of the GH-IGF1 axis in prepuberty is important for achieving normal testicular function in adulthood. Evaluating testicular growth over time in GHD children and measuring TV and sperm parameters in postpubertal GHD boys is advisable.

Keywords: GH; GHD; Spermatogenesis; Testicular function; Testis.

Fig. 1

Flowchart of patient enrollment in the study. From a total of 115 patients with growth hormone deficiency (GHD) of our previous cohort study , 89 were excluded due to gonadal or urogenital disorders, systemic diseases, cancer, age < 16 years, or non-participation in the study. A total of 26 patients met our inclusion criteria and were ultimately enrolled.

Fig. 2

Testicular growth of patients with growth hormone (GH) deficiency (GHD) during the period treatment with recombinant human GH. The blue diamonds represent the mean testicular volume in patients with growth hormone deficiency (GHD) enrolled in the study, from the age of 7 to 18 years. The yellow triangles represent the mean testicular volume in a published healthy cohort in the same age interval . All values were measured using a Prader orchidometer. The detail of the values is summarized in Supplementary Table 1. *p < 0.05 vs. GHD patients, Student t-test. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 3

Conventional sperm parameters in patients with growth hormone deficiency (GHD) and controls. GHD patients had significantly lower semen volume, total sperm count and progressive and total motility than healthy controls. No significant difference was found in sperm concentration and percentage of spermatozoa with normal morphology. Student’s t-test for independent samples or Mann-Whitney U test for normally and non-normally distributed variables were used, respectively. *p < 0.05; *p < 0.005.

Fig. 4

Testicular volume (TV) in patients with growth hormone deficiency (GHD) and controls. GHD Patients showed significantly lower right, left, and total TV, as measure by ultrasound scan, as compared to healthy controls. Student’s t-test for independent samples or Mann-Whitney U test for normally and non-normally distributed variables were used, respectively. *p < 0.005.