Ghrelin suppresses secretion of FSH in males

Background  Ghrelin decreases the secretion of LH probably by suppressing the release of hypothalamic GnRH. So far however, there is no evidence that ghrelin affects also the secretion of FSH in humans, the other gonadotrophin regulated by GnRH.
Objective  Our objective was to study the effect of ghrelin on secretion of FSH in humans.
Design/study subjects  Nocturnal (20:00–07:00 h) secretion profiles of FSH were measured in 10 healthy males (25·3 ± 3·2 years) twice, receiving 50 µg ghrelin or placebo at 22:00, 23:00, 24:00, and 01:00 h, in this single-blind, randomized, cross-over study.
Results  Mean FSH plasma levels were significantly ( P <  0·05) lower with ghrelin than placebo between 01:00 and 02:20. Consistently, a significant decrease from baseline was only observed in the ghrelin but not in the placebo condition.
Conclusion  This study provides first evidence that ghrelin suppresses the secretion of FSH in humans.