Differential Role of μ- and κ-Opiate Receptors in Anterior Pituitary Hormone Secretion
Morphine and other opioids are known to affect the release of most anterior pituitary hormones. These actions are thought to be mediated by an interaction with hypothalamic factors which are secreted into the hypothalamo-pituitary circulation (for review see Illes 1989; Pfeiffer and Herz 1984; Millan and Herz 1985). The presence of at least three distinct types of opiate receptors named μ (my), δ (delta) and κ (kappa) is generally accepted and ligands which selectively activate or block these receptors are now available. The existence of several distinct subtypes of opiate receptors not only adds another level of complexity to the analysis of opioid systems; it also raises the question whether there may exist particular physiological functions of, for example, μ- or κ-opiate receptors. In this case, it may become possible to selectively manipulate certain aspects of the endocrine function of opioids.
KeywordsLuteinizing Hormone Corticotropin Release Hormone Endogenous Opioid Opiate Receptor Luteinizing Hormone Release Hormone
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