Feeding is influenced by hypothalamic neuropeptides that promote (orexigenic peptides) or inhibit feeding. Of these, neuropeptide Y (NPY) in the arcuate nucleus and melanin-concentrating hormone (MCH) and orexins/hypocretins in the lateral hypothalamus have received attention because their expression is increased during fasting and because they promote feeding when administered centrally. Surprisingly, absence of the orexigenic neuropeptide NPY fails to alter feeding or body weight in normal mice. As deficiency of a single component of the pathway that limits food intake (such as leptin or receptors for melanocortin-4) causes obesity, it has been suggested that orexigenic signals are more redundant than those limiting food intake. To define further the physiological role of MCH and to test the redundancy of orexigenic signals, we generated mice carrying a targeted deletion of the MCH gene. MCH-deficient mice have reduced body weight and leanness due to hypophagia (reduced feeding) and an inappropriately increased metabolic rate, despite their reduced amounts of both leptin and arcuate nucleus pro-opiomelanocortin messenger RNA. Our results show that MCH is a critical regulator of feeding and energy balance which acts downstream of leptin and the melanocortin system, and that deletion of a gene encoding a single orexigenic peptide can result in leanness.

Male gender and older age are risk factors for IH. Pituitary enlargement is sensitive and specific for IH in the appropriate setting, can precede the clinical diagnosis, and resolves rapidly. Anterior pituitary function recovery is uncommon. The incidence of hypophysitis may positively predict survival in melanoma patients treated with Ipi.

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IntroductionIn mammals obesity results when caloric intake exceeds energy use (1). Information on the pathways regulating both feeding and energy expenditure has expanded remarkably in the past several years, and a number of novel hypothalamic peptides that either stimulate or inhibit feeding have been described (1). Among these peptides, melanin-concentrating hormone (MCH) is known to play an important role in feeding behavior (2-4). In the brain, MCH expression is limited to the lateral hypothalamus (5) and responds to nutritional signals, including fasting and leptin deficiency (3). Thus, expression is increased with fasting and is also markedly increased in the Lep ob /Lep ob mouse, which lacks leptin (3). When administered intracerebroventricularly (ICV), MCH leads to a rapid increase in feeding in rats (3, 4). Importantly, MCH ablation in mice leads to a syndrome of leanness associated with hypophagia and a relative increase in oxygen consumption (6).The lean phenotype of MCH-ablated mice is of particular interest (6), in that genetic ablation of neuropeptide-Y (NPY), another appetite-stimulating neuropeptide (7, 8), does not affect body weight (9) unless combined with other obesity genes (10). Indeed, MCH is thus far the only known hypothalamic peptide whose ablation results in leanness. This is in contrast to the number of peptides whose mutation or ablation leads to obesity. These peptides include leptin and the melanocortin-4 receptors (11), proopiomelanocortin (POMC) (12), and the serotonin IIC receptor (13).As MCH is a significant regulator of body weight whose absence leads to decreased percentage of body adiposity, we examined the possibility that overexpression of MCH eutopically in the lateral hypothalamus might lead to a syndrome of obesity. To examine this question we generated a line of transgenic animals overexpressing MCH (MCH-OE) in the lateral hypothalamus. On the original FVB background, mice were not obese on a standard diet. However, they became obese when the gene was bred to homozygosity and the animals were fed a high-fat diet. MCH-OE animals were hyperphagic, hyperleptinemic, and had higher blood glucose levels. Animals were also significantly hyperinsulinemic and failed to respond to an insulin challenge. Several lines of investigation suggest that the hypothalamic neuropeptide melanin-concentrating hormone (MCH) regulates body weight in mammals. Obese mice lacking functional leptin overexpress the MCH message in the fed or fasted state. Acute intracerebroventricular injection of MCH increases energy intake in rats. Mice lacking the MCH gene are lean. To test the hypothesis that chronic overexpression of MCH in mice causes obesity, we produced transgenic mice that overexpress MCH (MCH-OE) in the lateral hypothalamus at approximately twofold higher levels than normal mice. On the FVB genetic background, homozygous transgenic animals fed a high-fat diet ate 10% more and were 12% heavier at 13 weeks of age than wild-type animals, and they had higher systemic leptin levels. Blood gluco...

Recent studies have identified several neuropeptide systems in the hypothalamus that are critical in the regulation of body weight. The lateral hypothalamic area (LHA) has long been considered essential in regulating food intake and body weight. Two neuropeptides, melanin-concentrating hormone (MCH) and the orexins (ORX), are localized in the LHA and provide diffuse innervation of the neuraxis, including monosynaptic projections to the cerebral cortex and autonomic preganglionic neurons. Therefore, MCH and ORX neurons may regulate both cognitive and autonomic aspects of food intake and body weight regulation. The arcuate nucleus also is critical in the regulation of body weight, because it contains neurons that express leptin receptors, neuropeptide Y (NPY), alpha-melanin-stimulating hormone (alpha-MSH), and agouti-related peptide (AgRP). In this study, we examined the relationships of these peptidergic systems by using dual-label immunohistochemistry or in situ hybridization in rat, mouse, and human brains. In the normal rat, mouse, and human brain, ORX and MCH neurons make up segregated populations. In addition, we found that AgRP- and NPY-immunoreactive neurons are present in the medial division of the human arcuate nucleus, whereas alpha-MSH-immunoreactive neurons are found in the lateral arcuate nucleus. In humans, AgRP projections were widespread in the hypothalamus, but they were especially dense in the paraventricular nucleus and the perifornical area. Moreover, in both rat and human, MCH and ORX neurons receive innervation from NPY-, AgRP-, and alpha-MSH-immunoreactive fibers. Projections from populations of leptin-responsive neurons in the mediobasal hypothalamus to MCH and ORX cells in the LHA may link peripheral metabolic cues with the cortical mantle and may play a critical role in the regulation of feeding behavior and body weight.

Cushing disease is caused by a corticotroph tumor of the pituitary gland. Patients with Cushing disease are usually treated with transsphenoidal surgery, as this approach leads to remission in 70-90% of cases and is associated with low morbidity when performed by experienced pituitary gland surgeons. Nonetheless, among patients in postoperative remission, the risk of recurrence of Cushing disease could reach 20-25% at 10 years after surgery. Patients with persistent or recurrent Cushing disease might, therefore, benefit from a second pituitary operation (which leads to remission in 50-70% of cases), radiation therapy to the pituitary gland or bilateral adrenalectomy. Remission after radiation therapy occurs in ∼85% of patients with Cushing disease after a considerable latency period. Interim medical therapy is generally advisable after patients receive radiation therapy because of the long latency period. Bilateral adrenalectomy might be considered in patients who do not improve following transsphenoidal surgery, particularly patients who are very ill and require rapid control of hypercortisolism, or those wishing to avoid the risk of hypopituitarism associated with radiation therapy. Adrenalectomized patients require lifelong adrenal hormone replacement and are at risk of Nelson syndrome. The development of medical therapies with improved efficacy might influence the management of this challenging condition.

Context Primary adrenal insufficiency is an important clinical manifestation of X-linked adrenoleukodystrophy (ALD). Other manifestations include spinal cord disease and/or inflammatory demyelinating cerebral disease. Implementation of newborn screening requires natural history data to develop follow-up recommendations. Objective To delineate the natural history of adrenal insufficiency in male patients with ALD and to assess associations between the risk for developing adrenal insufficiency, spinal cord disease, or cerebral disease and plasma C26:0/C22:0 and C24:0/C22:0 ratios, which are diagnostic biomarkers for ALD. Design Retrospective review of medical records. Setting Two international tertiary referral centers of expertise for ALD. Patients Male patients with ALD followed at the centers between 2002 and 2016. Main Outcome Measures The primary endpoint was adrenal insufficiency; secondary endpoints were spinal cord and cerebral disease. Results Data on 159 male patients was available. The probability of developing adrenal insufficiency was described with survival analysis. Median time until adrenal insufficiency was 14 years (95% CI, 9.70 to 18.30 years). The cumulative proportion of patients who developed adrenal insufficiency was age-dependent and highest in early childhood [0 to 10 years, 46.8% (SEM 0.041%); 11 to 40 years, 28.6% (SEM, 0.037%); >40 years, 5.6% (SEM, 0.038%)]. No association between clinical manifestations and plasma ratios was detected with Cox model or Spearman correlation. Conclusions Lifetime prevalence of adrenal insufficiency in male patients with ALD is ~80%. Adrenal insufficiency risk is time-dependent and warrants age-dependent follow-up. Besides on-demand testing if symptoms manifest, we suggest a minimum of adrenal testing every 4 to 6 months for patients age ≤10 years, annual testing for those age 11 to 40 years, and solely on-demand testing for those age >40 years.

Objective Little has been published describing hypophysitis after nivolumab or pembrolizumab treatment. We aimed to (i) assess the risk of hypophysitis following nivolumab or pembrolizumab treatment, (ii) characterize the clinical presentation and outcomes in these patients and (iii) compare these patients to hypophysitis following ipilimumab and ipilimumab plus nivolumab (combo). We hypothesized that headaches, pituitary enlargement on MRI and multiple anterior pituitary hormone deficiencies would occur less often in the nivolumab/pembrolizumab group versus ipilimumab or combo hypophysitis patients. Design and methods We conducted a multi-center retrospective review utilizing the Research Patient Database registry to evaluate individuals diagnosed with hypophysitis following treatment with nivolumab/pembrolizumab (n = 22), ipilimumab (n = 64) and combo (n = 20). Encounter notes, radiologic imaging and laboratory results for these patients were comprehensively reviewed. Results Hypophysitis was rare following treatment with nivolumab/pembrolizumab (0.5%, 17/3522) compared to ipilimumab (13.6%, 34/250), P < 0.0001. Hypophysitis was diagnosed later in nivolumab/pembrolizumab (median: 25.8 weeks, interquartile range (IR): 18.4–44.0) compared to ipilimumab (9.3, IR: 7.2–11.1) or combo patients (12.5, IR: 7.4–18.6), P < 0.0001 for both. Headache and pituitary enlargement occurred less commonly in nivolumab/pemrolizumab patients (23% and 5/18, respectively) compared to ipilimumab (75%, 60/61) and combo (75%, 16/17) treatment groups (P < 0.0001 versus ipilimumab and P = 0.001 versus combo for headache and P < 0.0001 for both for enlargement). Conclusions This study represents the first comprehensive cohort analysis of nivolumab or pembrolizumab-associated hypophysitis in a large patient group. Hypophysitis occurs rarely with these medications, and these patients have a distinct phenotype compared to hypophysitis after treatment with ipilimumab or ipilimumab plus nivolumab.