Hypothalamic ghrelin administration inhibits spermatogenesis and reduces plasma testosterone in mice

MARIA BELEN PORETTI; CAMILA FRAUTSCHI; BIANCONI SANCIAGO; ANA CAROLINA MARTINI; EUGENIA LUQUE; LAURA VICENTI; MARTA FIOL DE CUNEO; VALERIA PAOLA CARLINI

Córdoba

Jornada; XV Jornada de Investigación Científica de la Facultad de Ciencias Médicas.; 2014

Secretaria de Ciencia y Tecnología. Facultad de Ciencias Medicas. Universidad Nacional de Córdoba

Ghrelin (Ghr), the natural ligand for the growth hormone secretagogue receptor (GHSR) discovered in 1999, is a peptide secreted in stomach and hypothalamus. It has been reported that Ghr and its specific receptor are synthesized in numerous sites of the reproductive tract, suggesting that beyond the effects of peptide on testicular steroidogenesis, it could directly affect other testicular processes, such as spermatogenesis. In this study, we investigated the effects of chronic Ghr administration (42 days) in the hypothalamus on morphometry and histology of testicle and plasma testosterone concentration (PTC). Adult male Albino?s Swiss mice (10 per treatment) were intrahypothalamic implanted with osmotic pumps (0.15 µl per hour) and infused with saline or different Ghr doses (0.3 or 3.0 nmol/μl). Testicular histology and morphometry were determined after treatment, evaluating: seminiferous tubule diameter, length and area of the seminiferous epithelium, number of germ cells (spermatogonia, spermatocytes, spermatids and sperm), Sertoli and Leydig cells. Twenty histological sections were obtained at regular intervals and counted germ cells at various stages of development in a prescribed area, expressed as the mean cell type / total germ cells ± SE in percentage. Sertoli and Leydig cells were counted, which expressed as the mean cell type / cell (somatic + interstitial) percentage ± SE. Testicular morphometry analyzes were performed taking into account 50 tubules per animal. Data were analyzed by ANOVA-Bonferroni (Statistic7). The PTC data were previously log-transformed. Results shows that administration of Ghr 3.0 nmol/µl for 42 days induced a significant decrease in the percentage of spermatogonia and spermatozoa (F = 2, 1492, df = 12, p ≤ 0.05). There were no significant difference neither in morphometric parameters studied nor in percentage of Sertoli and Leydig cells (p> 0.05). Ghrelin 3.0 nmol/µl significantly decreased plasma testosterone levels (F = 16.69, df = 2, p ≤ 0.05). This work provides new evidence on the effects of chronic Ghr administration on the male reproductive system, indicating that the peptide induces negative central modulation, affecting spermatogenesis, results that could correlate with a reduction in PTC.