The physiological regulation of the hypothalamus is well understood, but the functional relationships among neuroendocrine cells are less clear. Current research focuses on individual populations of neurons within this area of the brain, which synthesize and secrete a variety of peptide-releasing hormones, such as corticotropin-releasing factor. In this book it is described how one set of cells may synthesize several neuropeptides and how their expression can be differentially regulated by a combination of neuronal control and hormonal feedback. Reciprocal interactions between peptides, for example somatostatin and growth hormone-releasing hormone in the secretion of growth hormone, occur both in the hypothalamus and in the pituitary. The releasing hormones trigger secretion of pituitary hormones, e.g. follicle-stimulating hormone, which then act on target organs such as the gonads and the thyroid. Sex hormones complete the loop, influencing the activity of the hypothalamus and pituitary. The book concentrates on the regulation of hormone synthesis and release in the hypothalamus, and the coordinated production of the different hormones. It describes synthesis of the neuropeptides and the distributions of their binding sites, the roles of different cell types in the hypothalamus, and neuronal control of cellular functions. There is a report of the development of an immortal line of hypothalamic neurons that secrete gonadotropin-releasing hormone, which should facilitate molecular studies. A complementary technique described here is the use of a neurotropic vector to express foreign genes in the central nervous system. The physiology of the integrated feedback systems is also considered and there is an interesting account of how transplantation of hypothalamic tissue is able to restore reproductive function to genetically deficient mice.
Partial table of contents:
Peptidergic Neurotransmitters in the Endocrine Hypothalamus (M. Palkovits).
Co-Localization of Neuroactive Substances in the Endocrine Hypothalamus (P. Sawchenko, et al.).
Intrahypothalamic Neurohormonal Interactions in the Control of Growth Hormone Secretion
What Can We Learn from Sampling Hypophysial Portal Blood? (I. Clarke).
Regulation of Gene Expression in the Hypothalamus: Hybridization Histochemical Studies (W. Young).
Feedback Regulation of Thyrotropin-Releasing Hormone Gene Expression by Thyroid Hormone in the Hypothalamic Paraventricular Nucleus (R. Lechan & I. Kakucska).
Neural Control of the Synthesis and Release of Luteinizing Hormone-Releasing Hormone