Cushing’s syndrome is commonly complicated with an impairment of glucose metabolism, which is often clinically manifested as diabetes mellitus. The development of diabetes mellitus in Cushing’s syndrome is both a direct and indirect consequence of glucocorticoid excess. Indeed, glucocorticoid excess induces a stimulation of gluconeogenesis in the liver as well as an inhibition of insulin sensitivity both in the liver and in the skeletal muscles, which represent the most important sites responsible for glucose metabolism. In particular, glucocorticoid excess stimulates the expression of several key enzymes involved in the process of gluconeogenesis, with a consequent increase of glucose production, and induces an impairment of insulin sensitivity either directly by interfering with the insulin receptor signaling pathway or indirectly, through the stimulation of lipolysis and proteolysis and the consequent increase of fatty acids and amino acids, which contribute to the development of insulin resistance. Moreover, the peculiar distribution of adipose tissue throughout the body, with the predominance of visceral adipose tissue, significantly contributes to the worsening of insulin resistance and the development of a metabolic syndrome, which participates in the occurrence and maintenance of the impairment of glucose tolerance. Finally, glucocorticoid excess is able to impair insulin secretion as well as act at the level of the pancreatic beta cells, where it inhibits different steps of the insulin secretion process. This phenomenon is probably responsible for the passage from an impairment of glucose tolerance to an overt diabetes mellitus in susceptible patients with Cushing’s syndrome.

Introduction: Hyperprolactinemia has been implicated in the pathogenesis of obesity and glucose intolerance and is reportedly associated with an impaired metabolic profile. The current study aimed at investigating the effects of 12- and 60-month treatment with cabergoline (CAB) on metabolic syndrome (MetS) in patients with prolactinomas. Patients and Methods: 61 patients with prolactinomas (13 men, 48 women, 41 with microadenoma, 20 with macroadenoma), aged 34.4 ± 10.3 years, entered the study. In all patients, prolactin (PRL) and metabolic parameters were assessed at diagnosis and after 12 and 60 months of continuous CAB treatment. MetS was diagnosed according to NCEP-ATP III criteria. Results: Compared to baseline, CAB induced a significant decrease in PRL with complete normalization in 93% of patients after the 60-month treatment. At baseline, MetS prevalence was significantly higher in patients with PRL above (34.5%) than in those with PRL lower (12.5%) than the median (129 μg/l, p = 0.03). MetS prevalence significantly decreased after 12 (11.5%, p = 0.039) and 60 (5.0%, p = 0.001) months compared to baseline (28.0%). At both evaluations the lipid profile significantly improved compared to baseline. Fasting insulin and homeostatic model assessment of insulin resistance significantly decreased after 1 year of CAB (p = 0.012 and p = 0.002, respectively) and further improved after 60 months (p = 0.000). The visceral adiposity index significantly decreased after the 60-month treatment (p = 0.000) compared to baseline. At the 5-year evaluation CAB dose was the best predictor of percent decrease in fasting insulin (t = 2.35, p = 0.022). Conclusions: CAB significantly reduces MetS prevalence and improves the adipose tissue dysfunction index. The improvement in PRL, insulin sensitivity and other metabolic parameters might reflect the direct effect of CAB.

All 3 investigated local anesthetics were found to be clinically comparable despite the slight reduction of early postoperative motor block associated with the use of ropivacaine.