ENV341H1 Lecture Notes - Stockholm Convention On Persistent Organic Pollutants, Hypospadias, Cryptorchidism

Endocrine disrupting chemicals (EDCs) can act by binding directly to hormone receptors as hormone “mimics” or as “antagonists”. Describe the key difference in mechanism between mimics and antagonists in terms of the effects on receptor signaling. Why is it important to know the potencies of different EDCs relative to normal estrogen or other relevant hormones for understanding the potential human health effects from exposure to EDCs?

Somatostatin is an inhibitoryendocrine hormone. Many animal tissuecells reduce their activity levels when they bind molecules ofsomatostatin by receptors. Some cells within the hypothalamus ofanimals secrete somatostatin to reduce the activity of some otherhypothalamic endocrine cells. Somatostatin is also released bycells in the pancreatic Islets of Langerhans to control activity ofinsulin and glucagon secreting cells. But the somatostatin releasedin the hypothalamus does not interfere with regulation of Isletcells and somatostatin released in the Islets does not affecthypothalamic cells.

Hypothesize and explain why endocrine release ofsomatostatin from cells in each of these two locations does notinterfere with hormone release from the endocrine cells in theother location.