Hypothalamic control of body weight
Principal Research Findings
Our principal research objective is to understand how the central nervous system controls body composition by receiving and initiating endocrine signals. In particular, we are interested in discovering how certain peripheral signals regulate the activity of discrete populations of cells in the hypothalamus, and the consequences of this action for feeding behaviour, for altering hormone secretion and for regulating body composition.
In 1993, we demonstrated for the first time that synthetic growth hormone secretagogues activate cells in the hypothalamus. This paved the way towards identifying the hypothalamic circuits through which these agents operate: their neurochemical identity, projections, neuroendocrine status and function (See Dickson et al., Neuroscience 53:303-306).
In 1997, we demonstrated that, in addition to activating the GH-releasing hormone neurones, the growth hormone secretagogues also activate neuropeptide Y (NPY)-containing cells. As these NPY neurones are known to participate in central feeding circuits we have gone on to address possible roles of the growth hormone secretagogues in body weight control (See Dickson & Luckman, Endocrinology: 138:771-777).
More recently, in chronic studies we have begun to investigate growth hormone-independent actions of growth hormone secretagogues. We demonstrated, for the first time, that that these compounds induce adiposity by a mechanism that is likely to include increased feeding. This together with their growth hormone-releasing activities raises important questions regarding the therapeutic potential of these compounds to alter body composition beneficially, particularly in catabolic states (See Lall et al., BBRC, 280: 132-138).