Extracellular Potassium Change in the Rat Adenohypophysis: An Indicator of Neurohypophyseal-Adenohypophyseal Communication
It has been generally thought that hypothalamic releasing and inhibiting factors are secreted from nerve terminals of the median eminence into long portal vessels, and transported in plasma toward the anterior pituitary gland. Scanning electron microscopy of pituitary vascular casts revealed, however, that the median eminence, the posterior lobe, and the anterior lobe were interconnected by portal vessels (Page and Bergland, 1977). Further, numerous compounds with anterior lobe hormone-releasing and -inhibiting activity have been identified in the posterior lobe. Thus, posterior lobe compounds may reach the anterior lobe, as suggested by Porter et al. (1977), and modulate adenohypophyseal hormone secretions; alternatively, adenohypophyseal hormones may reach the posterior lobe (Page and Bergland, 1977).
KeywordsCorticotropin Release Factor Median Eminence Anterior Lobe Posterior Lobe Pituitary Stalk
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