Superior cervical ganglionectomy effects on median eminence and anterior and mediobasal hypothalamic taurine content in male rats: effects of hyperprolactinemia.

The neuroendocrine sequelae of acute or chronic superior cervical ganglionectomy in control or pituitary-grafted rats were studied by analyzing both plasma prolactin, growth hormone (GH) and ACTH levels, and taurine (TAU) content in the hypophysiotropic area of the hypothalamus or the median eminence. As expected, after either acute or chronic ganglionectomy, norepinephrine (NE) content decreased in the brain areas studied, although the values remained higher in hyperprolactinemic rats. TAU content was differentially modified by acute vs. chronic surgeries, thus indicating the possible existence of hypothalamic interactions between TAU and NE to regulate pituitary hormone secretion. Indeed, associated differential changes in plasma prolactin, GH and ACTH levels may be due to the observed TAU changes. As expected, pituitary grafting increased plasma prolactin, GH and ACTH levels, so that the presence of a pituitary graft differentially interferes with the effects of either surgery not only on TAU content but also on the plasma levels of the hormone studied. Globally, ongoing studies confirm the differential effects of acute and chronic superior cervical ganglionectomy on plasma prolactin, GH and ACTH levels, and provide new evidence about its effects on TAU content in the hypophysiotropic area of the hypothalamus and the median eminence that may partially explain the changes observed in the pituitary hormones studied.