Endotoxins and endocrine system.

There is good evidence for the interaction of neuroendocrine and immune systems. Endotoxin (LPS)-induced mediators (e.g., cytokines, prostaglandins etc) set on endocrine organs (e.g., the hypothalamo-pituitry-adrenal axis; thyroid glands etc). Endotoxin-treated, intestinal ischemic, or irradiated rats show decreased T4 levels of blood. These animals cannot respond to TSH because the TSH-receptors of follicular membranes are disturbed by LPS in the thyroid glands. Radiodetoxified endotoxin is an effective immunstimulator and does not disturb the follicular membrane of thyroid gland. Thus, the T4 production remains normal. The bile acids--as the end-product of cholesterol metabolism--play an important role in the physiological defense of macroorganisms against endotoxin and other lipid-like agents (Physico-chemical defense) and in the regulation of endocrine system, including the reproduction.