Leptin effect on nitric oxide and GnRH-induced FSH secretion from ovine pituitary cells in vitro

The secretion of gonadotrophins from anterior pituitary cells can be modulated by leptin and signals originating from the immune system, among others, by nitric oxide (NO). There are some studies that have demonstrated a role for leptin and NO in the regulation of FSH in rodents, however, no similar data are available in regard to ewes. Therefore, the objective of the present study was to analyse the leptin effect on GnRH-induced FSH secretion from the ovine anterior pituitary cells in vitro. Additionally, the influence of leptin on NO release and its role in the GnRH and leptin–modulated secretion of FSH from pituitary gland of ewes was investigated. The obtained results show that the influence of leptin on FSH secretion is biphasic. Leptin in concentration 10-8 and 10-7 M/l significantly enhances, whereas 10-6 and 10-5 M/l of leptin suppresses FSH secretion from the pituitary cells in comparison to the control. The secretion of FSH and NO release under the influence of leptin are in very high positive correlation (r=0.77). The inhibition of NO synthesis with L-NAME, instead, disables leptin from the stimulation of FSH secretion.