The Pineal Gland And Its Hormones

This volume contains the written contributions to the proceedings of a workshop related to the pineal gland and its hormones, which was held in Erice, Italy, on June 7 -June 13, 1994. This series of workshops, which began in 1982 and which have been held at four-year intervals since that time, has provided important continuity for advancing the state of knowledge relating to this very important investigative area. The enthusiasm for these conferences has increased steadily, as reflected in the number of individuals applying to attend and in the input of individuals who participate in the meeting. The 1994 meeting was important because of its timeliness. In the two years preceding the meeting a number of revolutionary discoveries were made relative to the actions of the pineal hormone melatonin. The Xenopus melatonin receptor was cloned, melatonin was demonstrated to be a potent antioxidant, the significance of melatonin receptors at the level of pars tuberalis in the regulation of the hypothalamo-pituitary-gonadal axis was questioned, a number of melatonin receptor analogues were discovered and successfully utilized, the mechanisms by which melatonin retards initiation and promotion of cancer was further elucidated, the clinical aspects of the pineal gland was re-scrutinized. Reviews relating to each of these subjects, as well as many others, are contained in this proceedings book. This volume represents an up-to-date repository for the most recent information related to this rapidly advancing field.

The pineal gland has been a subject of interest and speculation for more than 2000 years. Greek anatomists were impressed by the ob servation that the pineal gland is an unpaired structure and they believed that it regulated the flow of thoughts. The philosopher Descartes proposed an important role for this organ in brain function. At the beginning of the 20th century experiments by several investi gators indicated that the pineal influenced sexual function and skin pigmentation and was also responsive to light signals. With the iso lation of melatonin from bovine pineal glands by Lerner and cowork ers in 1958 the modern era of pineal research was initiated. Within a few years the pathway for the biosynthesis of melatonin in the pineal was elucidated. Soon thereafter it was shown that the formation of melatonin was influenced by environmental lighting. Ana tomists found that the pineal was innervated by sympathetic nerves and that the gland had photoreceptor elements. It was also shown that the gonads were influenced by light via the pineal gland. Research on the pineal gland became of increasing interest to anatomists, bioche mists, pharmacologists and endocrinologists. With the expanding know ledge concerning the function of the pineal gland contributed by the wide variety of disciplines, it was thought that a study workshop would be timely.

The link between the pineal gland and cancer is a rapidly emerging research field due to promising experimental and clinical trials with melatonin. The pineal gland acts as a transducer of environmental light to regulate rhythmic processes, including reproductive function in seasonally breeding animals and the entrainment of circadian rhythms, such as the sleep-wake cycle, in man. This book elucidates the physiological significance of the pineal gland and surveys phenomena and mechanisms of pineal - tumor interaction at the neuroendocrine, neuroimmune, neural, and molecular levels. Yet unidentified low-molecular-weight pineal substances with tumor-inhibiting capacity, a possible involvement of melatonin in electromagnetic field effects on cancer, and the oncotherapeutic potential of melatonin are also addressed. The encouraging results should incite further research to elucidate the exact nature of the link between the pineal gland and cancer for the benefit of patients.

This book is designed as an introductory text in neuroendocrinology; the study of the interaction between the brain and endocrine system and the influence of this on behaviour. The endocrine glands, pituitary gland and hypothalamus and their interactions and hormones are discussed. The action of steroid and thyroid hormone receptors and the regulation of target cell response to hormones is examined. The function of neuropeptides is discussed with respect to the neuroendocrine system and behaviour. The neuroimmune system and lymphokines are described and the interaction between the neuroendocrine and neuroimmune systems discussed. Finally, methods for studying hormonal influences on behaviour are outlined. Each chapter has review and essay questions designed for advanced students and honours or graduate students with a background in neuroscience, respectively.

This volume provides the reader with an overview of an intriguing and interdisciplinary field of research. For the first time the mammalian pineal gland, its mode of action and its physiological effects are discussed in a comprehensive, single-authored work.