Endocrine Abstracts

Follicle-stimulating hormone (FSH) is a member of the glycoprotein hormone family that plays a pivotal role in ovarian folliculogenesis and spermatogenesis. FSH receptor (FSHR) is, indeed, highly expressed in granulosa and Sertoli cells respectively. However, recent studies have detected FSHR also in extra-gonadal tissues, such as adipose tissue, bone, endometrium, placenta, endothelium, monocytes, and malignant tissues, suggesting, that the activity of this hormone may not be limited to fertility regulation. Although the role of FSH in extra-gonadal tissues is an interesting topic, the effect of FSH in endothelial tissue has been poorly studied and the findings are sometimes discordant, mainly about angiogenic effect of FSH. However, a recent study has observed an increased vascular cell adhesion molecule-1 (VCAM-1) expression in endothelial cells after FSH treatment, suggesting a role of this hormone in the development of atherosclerosis. In this study, we aimed to evaluate the effects of FSH on human umbilical cord vein endothelial cells (HUVEC) as cell model. Wound healing and tube formation assay were performed to investigate respectively cell migration and tube length in cells treated with 5, 25, 50 mUI/ml of rhFSH for 24h and shear stress assay was performed to measure Nitric Oxide (NO) production after 24h of treatment with the same doses of rhFSH. Furthermore, we used Elisa assay to quantify eNOS (endothelial Nitric Oxide Synthase) phosphorylation and Inositol Triphosphate (IP3) production, and Fluo4-probe and immunofluorescence to assess Ca²⁺ level and VE-cadherin localization, respectively. Wound-healing and tube formation assays did not highlight any significant difference, whilst NO production and Ca²⁺level increased after stimulation with 25 and 50mUI/ml of FSH compared to controls or cells incubated with a low FSH dose (5mUI/ml). Furthermore, eNOS phosphorylation and IP3 increased after stimulation with 50 mUI/ml FSH, suggesting that FSH could exert its biological action via Pospholipase C (PLC)/Ca²⁺/Protein Kinase C (PKC) pathway. Although NO has a protective role in cardiovascular disease, however, over production of NO could result in a damaging effect on cellular membrane. In fact, immunofluorescence assay showed an anomalous localization of VE-cadherin, an adhesion molecule that is involved in the control of vascular permeability, after stimulation with 50 mUI/ml of FSH. This is the first study showing a putative molecular signaling triggered by FSH in endothelial cells. However, further experiments in vivo are necessary to clarify whether perturbation of FSH, similar to the one observed in menopause or hypergonadotropic hypogonadism, may affect endothelial function.