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.
KeywordsCatheter Estrogen Cage Cortisol Morphine
Unable to display preview. Download preview PDF.
- Krulich L, Koenig JI, Conway S, McCann SM, Mayfield MA (1986) Opioid κ-receptors and the secretion of PRL and GH in the rat. Neuroendocrinology 99: 411–418.Google Scholar
- Nikolarakis K, Pfeiffer A, Stalla GK, Herz A (1989) The role of the sympathetic nervous system and CRH in morphine-stimulated release of ACTH in rats. Brain Res (in press)Google Scholar
- Pechnik R, George R, Poland RE (1985) Identification of multiple opiate receptors through neuroendocrine responses. I. Effects of agonists. J Pharmacol Exp Ther 232: 163–169Google Scholar
- Stalla GK, Hartwimmer J, Kaliebe T, Müller OA (1985) Radioimmunoassay of human CRF. Acta Endocrinol [Suppl] (Copenh) 267: 108–118Google Scholar
- Tsagarakis S, Rees LH, Besser G M, Grossman A (1989) Opiate receptor subtype regulation of CRF-41 release from rat hypothalamus in vitro. Neuroendocrinology (in press)Google Scholar