Regulation of the hypothalamic corticotropin-releasing hormone neurosecretory system

The regional distribution of thyrotropin-releasing hormone (TRH) in rat brain was studied. The greatest concentration of TRH was found in the median eminence. High concentrations were also found in several hypothalamic nuclei. Outside the hypothalamus, relatively large amounts of TRH were found in the septal and preoptic areas.

Thyrotropin-Releasing Hormone in Specific Nuclei of Rat Brain

CHAPTER 9 – Control of Adrenocorticotropic Hormone Secretion

Steroid-sensitive neurones in rat brain: Anatomical localization and responses to neurohumours and ACTH

Neural control of anterior pituitary functions.

Electrical stimulation of various sites in the medial ventral hypothalami of adult female rats was done through chronically implanted electrodes in order to determine simultaneous effects on the pituitaryadrenal and thyroid systems. A series of stimulations (10 min daily, 4–9 days) delivered to preoptic, suprachiasmatic and anterior hypothalamic areas induced cytological activation of pars distalis basophils, markedly reduced pituitary thyrotrophin (TSH) stores, increased plasma TSH concentrations 4- to 5-fold, and resulted in histological stimulation of the thyroid gland. Comparable excitation of the posterior median eminence and arcuate nuclear regions of the tuberal hypothalamus produced effects of similar magnitude. The mere presence of electrodes in the hypothalamus without electrical stimulation had no significant effect on TSH secretion and histology of the thyroid, but caused adrenal hypertrophy and elevation of plasma corticosteroid levels in sham-stimulated rats. Excitation of the rostral or cau...

J. M. Grodin

Papers

Electrical Stimulation of the Hypothalamus: Simultaneous Effects on the Pituitary-Adrenal and Thyroid Systems of the Rat