After severe head trauma, gonadotrophin deficiency was the most common pituitary deficit. GH deficiency showed a prevalence similar to ACTH and TSH deficits, i.e. near 6% of the cohort. Taken together, 24.7% of the subjects studied showed any type of pituitary hormone deficiency.
The present results provide a cellular and molecular basis to support the desmopressin stimulation test as a reliable, specific test for the diagnosis and postsurgery prognosis of CD. Furthermore, our data indicate that AVPR1b is responsible for the direct/exclusive desmopressin stimulatory pituitary effects observed in CD, thus opening the possibility of exploring AVPR1b antagonists as potential therapeutic tools for CD treatment.
Growth and growth hormone (GH) secretion are blunted or severely impeded in chronic hypercortisolism and in patients with Cushing’s syndrome. A mechanistic explanation for the effect however has yet to be provided. On the other hand, several properties of ghrelin, a new peptide recently identified as the endogenous ligand of the GH secretagogue receptor, are still largely unknown. The two aims of this study were to observe whether ghrelin-mediated GH secretion was altered, and to characterize the corticotropin (ACTH) and cortisol response to this new stimulus in patients with Cushing’s disease. Ten patients with active Cushing’s disease (6 harboring microadenomas and 4 with macroadenomas) and 10 sex- and age-matched controls were studied. Ghrelin was administered at a dose of 1 µg/kg i.v. and GH, ACTH and cortisol analyzed in duplicate. In control women, ghrelin induced GH secretion to levels of 74.4 ± 12.8 µg/l, while chronic hypercortisolism severely reduced the ghrelin-mediated GH release in all patients with Cushing’s disease (peak values 17.7 ± 5.2 µg/l). The slightly, but significantly higher adiposity of patients vs. controls may have contributed to the effect, since a significant negative correlation (r = 0.639) was found between the amplitude of the GH peak and body mass index. In control women, ghrelin increased ACTH and cortisol levels, with peaks at 57.4 ± 19.0 ng/l and 162 ± 16 µg/l, respectively. This secretion was enhanced in Cushing’s syndrome patients, with ACTH and cortisol values of 380.7 ± 109.8 ng/l and 338 ± 81 µg/l respectively, both significantly higher than in controls. In conclusion, ghrelin-induced GH secretion was severely blunted in patients with active Cushing’s syndrome, in addition to a remarkable hyper-response in ACTH and cortisol secretion. These findings could have implications for the understanding of the physiology and physiopathology of interactions between GH and ACTH regulation.
Leptin, the product of the ob gene, is a recently discovered hormone secreted by adipocytes. Cushing's syndrome is a disease state usually associated with weight gain due to the accumulation of adipose tissue. In order to study the effect of chronic glucocorticoid excess upon serum leptin levels; in the present work, four patients with recently diagnosed Cushing's syndrome and a group of control subjects matched for age, sex and body mass index (BMI) were studied. Serum leptin concentrations, measured by radioimmunoassay, were assessed in samples taken every 60 minutes over a 24 hour period. Assessment of leptin concentrations over 24 hours, by means of the area under curve showed a twofold increase in serum leptin levels in patients with Cushing's syndrome (mean+/-SEM 54.3+/-14) in comparison to control subjects (29.3+/-4.4; p<0.05). In conclusion, our data show that leptin levels are markedly increased in Cushing's syndrome patients. The relevance of this finding to the increased body fat present in patients with Cushing's syndrome merits further studies.
Results provide evidence of cognitive and neurophysiological impairment, characterized by moderate-to-severe memory impairment and decreased neural activity in specific brain areas. High levels of GH and IGF-I in acromegaly patients could be the basis for these findings.
These results constitute the first demonstration that ghrelin acts directly on corticotrope tumor cells derived from patients with Cushing's disease. The presence of ghrelin and GHS-R suggests that pituitary ghrelin may play an autocrine/paracrine role in regulating ACTH release in Cushing's disease. Our findings provide a plausible cellular basis for the exaggerated ACTH response to ghrelin in Cushing's disease and suggest novel research strategies to develop medical treatments for this disease.
BIB induces a temporary sense of satiety in morbidly obese patients which is not mediated by modification of fasting or postprandial levels of plasma ghrelin.
Patients with active untreated acromegaly show mild to moderate neurocognitive disorders that are associated to chronic exposure to growth hormone (GH) and insulin-like growth factor (IGF-I) hypersecretion. However, it is unknown whether these disorders improve after controlling GH/IGF-I hypersecretion. The aim of this study was to compare neurocognitive functions of patients who successfully underwent GH-secreting adenoma transsphenoidal surgery (cured patients) with patients with naive acromegaly. In addition, we wanted to determine the impact of different clinical and biochemical variables on neurocognitive status in patients with active disease and after long-term cure. A battery of six standardized neuropsychological tests assessed attention, memory and executive functioning. In addition, a quantitative electroencephalography with Low-Resolution Electromagnetic Tomography (LORETA) solution was performed to obtain information about the neurophysiological state of the patients. Neurocognitive data was compared to that of a healthy control group. Multiple linear regression analysis was also conducted using clinical and hormonal parameters to obtain a set of independent predictors of neurocognitive state before and after cure. Both groups of patients scored significantly poorer than the healthy controls on memory tests, especially those assessing visual and verbal recall. Patients with cured acromegaly did not obtain better cognitive measures than naïve patients. Furthermore memory deficits were associated with decreased beta activity in left medial temporal cortex in both groups of patients. Regression analysis showed longer duration of untreated acromegaly was associated with more severe neurocognitive complications, regardless of the diagnostic group, whereas GH levels at the time of assessment was related to neurocognitive outcome only in naïve patients. Longer duration of post-operative biochemical remission of acromegaly was associated with better neurocognitive state. Overall, this data suggests that the effects of chronic exposure to GH/IGF-I hypersecretion could have long-term effects on brain functions.
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