Endocrine Abstracts

The hypothalamo-pituitary–thyroid (HPT) axis serves to maintain appropriate systemic levels of thyroid hormone (TH) through a negative feedback pathway via the hypothalamic arcuate and paraventricular nuclei. However, the effects of TH in other hypothalamic regions are poorly understood. Triiodothyronine (T3) administration to the hypothalamic ventromedial nucleus (VMN) induces a potent hyperphagic response, although it is unclear whether this is part of a nove...

Attenuated glucoprivic feeding responses are a feature of hypoglycaemic unawareness in insulin-treated diabetes. Glucose alters the activity of hypothalamic neurones involved in regulating appetite. Arcuate nucleus (ARC) Neuropeptide Y (NPY) releasing neurones stimulate feeding. The identification of glucose-sensitive NPY releasing hypothalamic neurones suggests a strong role for these neurones in mediating changes in appetite induced by alterations of glucose. To gain a bette...

The hypothalamus regulates multiple homeostatic systems, and is essential for the regulation of appetite and energy balance. Neuropeptide Y, a 36 amino acid peptide and member of the PP-fold family, is a key hypothalamic neuropeptide involved in the regulation of energy balance, potently stimulating food intake following central administration. NPY is expressed in the arcuate nucleus (ARC) and NPYergic neurones project to multiple hypothalamic nuclei and extra-hypothalamic sit...

Background and aims: Ghrelin is the only known peripheral hormone, which increases food intake. It is released from the stomach and is thought to function as a meal initiator and signal of energy deficit. We used bacterial artificial chromosome transgenesis to generate a mouse model with increased ghrelin expression and production in stomach and brain. These mice exhibited increased circulating bioactive ghrelin and as expected were hyperphagic and glucose intolerant. We hypot...

Hypoglycaemia and hypoglycaemia unawareness severely limit the optimal management of diabetes mellitus and cause recurrent morbidity and even mortality in intensively controlled patients. Altered hypothalamic glucose sensing has been implicated in the development of defective counter regulatory responses to insulin induced hypoglycaemia and hypoglycaemic unawareness. This change in hypothalamic glucose sensing has been attributed, at least in part, to an increase in glucokinas...

Relaxin-3 is a newly discovered member of the insulin superfamily. It is expressed in the nucleus incertus (NI) of the brainstem which has projections to the hypothalamus. Relaxin-3 binds with high affinity to the G-protein-coupled receptors RXFP1 and RXFP3. RXFP3 is expressed predominantly in the CNS, and in particular within the hypothalamic paraventricular nucleus (PVN). The physiological function of relaxin-3 is unknown but recent work suggests it may play a role in appeti...

The hypothalamo-pituitary–thyroid (HPT) axis maintains controlled systemic levels of thyroid hormone (TH). This is achieved through negative feedback via the hypothalamic arcuate and paraventricular nuclei. The effects of thyroid hormone in other hypothalamic nuclei are yet to be elucidated. Administration of triiodothyronine (T3, thyroid hormone) into the hypothalamic ventromedial nucleus (VMN) increases food intake in rats. Thyroid hormone activation and inac...

Alarin is the most recently discovered member of the galanin peptide family, and is encoded by a splice variant of galanin-like peptide (GALP) mRNA. Galanin and GALP are known to regulate energy homeostasis and reproduction. Galanin is thought to mediate its effects via the three-galanin receptors. GALP also binds to these known galanin receptors, but evidence suggests that it may also act via an as yet unknown GALP specific receptor. The role of alarin in energy homeostasis a...

3-iodothyronamine (T1AM) is a novel, endogenous rapid acting biogenic amine, which is a potent agonist of the G-protein coupled trace amine-associated receptor 1, TAAR1. It has been suggested that endogenous T1AM could be generated by enzymatic deiodonation and decarboxylation of T4. The presence of T1AM in rat brain and the distribution of the TAAR1 receptor in the hypothalamus suggest that T1AM may affect food intake and regulate e...

Prokineticin 2 (PK2) is a neuropeptide expressed in hypothalamic nuclei involved in the regulation of energy homeostasis, and has been shown to acutely reduce food intake in rodents. PK2 binds to and activates two G protein-coupled receptors, the PK receptor 1 (PKR1) and the PK receptor 2 (PKR2). We aimed to determine the sites and receptors which mediate the anorectic effects of peripherally administered PK2 within the CNS. We investigated neuronal activity in the hypothalamu...