**5.5.1 Endothelins**

Endothelins (ETs) are a family of vasoactive peptides secreted by vascular endothelium. ETs play autocrine/paracrine regulatory functions, acting via two subtypes of receptors, ET-A and ET-B. The endocrine cells in the glomerulosa cells of the adrenal cortex express both ET-A and ET-B. The cells of the zone fasciculata/reticularis mainly express ET-B. ETs stimulate the secretion of mineralocorticoids by glomerulosa cells. Its effects on glucocorticoid secretion are lower (Nussdorfer et al., 1997). The effects of ETs on steroidogenic cells are mediated through the activation of various signaling mechanisms, including the stimulation of phospholipase C, phospholipase A2 and adenyl cyclase activity, as well as calcium influx through plasma channels (Delarue et al., 2004).
