Management of pituitary incidentalomas.

Pituitary incidentalomas are common findings with increasing use of modern neuroradiological imaging undertaken for symptoms unrelated to pituitary disease. The prevalence of these lesions is ∼10% in autopsy studies and the incidence varies from 10% to 38% on magnetic resonance imaging in the published literature. They are almost always benign in nature and most are non-functioning (non-secreting) adenomas. Although many individuals are asymptomatic at diagnosis, some with functioning (secreting) pituitary adenomas or larger non-functioning adenomas have symptoms. All identified cases should have a thorough clinical and endocrinological evaluation to help with precise management, which depends on the size of the lesion, hormonal status (functioning versus non-functioning adenoma) and the presence of visual deficits resulting from optic nerve compression by the pituitary adenoma. Here, we provide an overview of the initial assessment and management of pituitary incidentalomas for clinicians not routinely involved in the management of pituitary disease.

The influence of Glucose-dependent Insulinotropic Polypeptide (GIP) on human adipose tissue and fat metabolism: Implications for obesity, type 2 diabetes and Non-Alcoholic Fatty Liver Disease (NAFLD).

Glucose-dependent insulinotropic polypeptide (GIP) and glucagon like peptide (GLP-1) are the two incretin hormones secreted by the enteroendocrine system in response to nutrient ingestion. Compared with GLP-1, GIP is less well studied as a hormone or as a potential pharmacological treatment. Beyond its insulinotropic effects in the pancreas, GIP has important biological actions in many other tissues but its role in dietary fat metabolism and lipid storage in adipose tissue has been most studied. It is still unclear if such effects of GIP on adipose tissue/fat metabolism are protective or deleterious in the long term. Antagonising GIP actions through genetic and chemical disruption in mice models prevented diet induced obesity and improved insulin sensitivity. Whilst such effects of GIP antagonism are yet to be evaluated in humans, recent studies using combined GIP and GLP-1 agonists have shown weight reduction and improved glycaemic control in people with type 2 diabetes (T2D). Therapeutic manipulation of GIP physiology is intriguing in that both agonists and antagonists of GIP are being investigated to explore their potential weight-reducing and other metabolic benefits in people with obesity, T2D and non-alcoholic fatty liver disease (NAFLD). This review will discuss the physiological effects of GIP on fat metabolism in human adipose and other non-adipose tissues such as liver, pancreas, skeletal muscle and heart, describe where the actions of GIP may contribute to the pathophysiology of obesity, T2D and NAFLD and finally describe the therapeutic implications of GIP antagonism and agonism in these conditions.

Glucose-dependent insulinotropic polypeptide promotes lipid deposition in subcutaneous adipocytes in obese type 2 diabetes patients: a maladaptive response.

Glucose-dependent insulinotropic polypeptide (GIP) beyond its insulinotropic effects may regulate postprandial lipid metabolism. Whereas the insulinotropic action of GIP is known to be impaired in type 2 diabetes mellitus (T2DM), its adipogenic effect is unknown. We hypothesized that GIP is anabolic in human subcutaneous adipose tissue (SAT) promoting triacylglycerol (TAG) deposition through reesterification of nonesterified fatty acids (NEFA), and this effect may differ according to obesity status or glucose tolerance. Twenty-three subjects categorized into four groups, normoglycemic lean (n = 6), normoglycemic obese (n = 6), obese with impaired glucose regulation (IGR; n = 6), and obese T2DM (n = 5), participated in a double-blind, randomized, crossover study involving a hyperglycemic clamp with a 240-min GIP infusion (2 pmol·kg-1·min-1) or normal saline. Insulin, NEFA, SAT-TAG content, and gene expression of key lipogenic enzymes were determined before and immediately after GIP/saline infusions. GIP lowered NEFA concentrations in the obese T2DM group despite diminished insulinotropic activity (mean NEFA AUC0-4 h ± SE, 41,992 ± 9,843 µmol·l-1·min-1 vs. 71,468 ± 13,605 with placebo, P = 0.039, 95% CI: 0.31-0.95). Additionally, GIP increased SAT-TAG in obese T2DM (1.78 ± 0.4 vs 0.86 ± 0.1-fold with placebo, P = 0.043, 95% CI: 0.1-1.8). Such effect with GIP was not observed in other three groups despite greater insulinotropic activity. Reduction in NEFA concentration with GIP correlated with adipose tissue insulin resistance for all subjects (Pearson, r = 0.56, P = 0.005). There were no significant gene expression changes in key SAT lipid metabolism enzymes. In conclusion, GIP appears to promote fat accretion and thus may exacerbate obesity and insulin resistance in T2DM.

Intracranial desmoplastic small round cell tumor presenting as a suprasellar mass.

Desmoplastic small round cell tumors (DSRCTs) are rare, aggressive neoplasms that typically arise from abdominal and pelvic peritoneum in young adults. Other primary sites are uncommon, and an intracranial origin is exceptionally rare. Here the authors report the first case of a DSRCT presenting as a primary suprasellar tumor causing panhypopituitarism and severe bitemporal hemianopia in a young man. Macroscopic debulking of the tumor was undertaken, and histology revealed features of DSRCT. Reverse transcription polymerase chain reaction confirmed the presence of Ewing's sarcoma-Wilms tumor 1 (EWS-WT1) gene rearrangement specific to DSRCT. Postoperative whole-body imaging showed no primary malignancy elsewhere. The tumor recurred 4 months after surgery, and this was followed by cervical and mediastinal lymph node metastases. The patient died 20 months after initial presentation of rapidly progressive disease. DSRCTs should be included in the differential diagnosis of an unusual suprasellar mass in young adults. Early diagnosis is essential, and once the tumor is identified histologically, gross-total resection and radical postoperative treatment involving radiotherapy, chemotherapy, and close surveillance are required because of the lesion's potential for rapidly progressive malignancy.