25-Hydroxycholecalciferol response to single oral cholecalciferol loading in the normal weight, overweight, and obese.

UNLABELLED: After a single cholecalciferol load, peak serum 25-hydroxycholecalciferol (25OHD) is lower in individuals with a higher body mass index (BMI), probably due to it being distributed in a greater volume. Its subsequent disappearance from the serum is slower the higher the individual's BMI, probably due to the combination of a larger body volume and a slower release into the circulation of vitamin D stored in adipose tissue. INTRODUCTION: The aim of the study is to examine 25-hydroxycholecalciferol (25OHD) response to a single oral load of cholecalciferol in the normal weight, overweight, and obese. METHODS: We considered 55 healthy women aged from 25 to 67 years (mean ± SD, 50.8 ± 9.5) with a BMI ranging from 18.7 to 42 kg/m(2) (mean ± SD, 27.1 ± 6.0). The sample was divided into three groups by BMI: 20 were normal weight (BMI ≤ 25 kg/m(2)), 21 overweight (25.1 ≤ BMI ≤ 29.9 kg/ m(2)), and 14 obese (BMI ≥ 30 kg/m(2)). Each subject was given 300,000 IU of cholecalciferol orally during lunch. A fasting blood test was obtained before cholecalciferol loading and then 7, 30, and 90 days afterwards to measure serum 25OHD, 1,25 dihydroxyvitamin D [1,25 (OH)2D], parathyroid hormone (PTH), calcium (Ca), and phosphorus (P). Participants' absolute fat mass was measured using dual energy X-ray absorptiometry (DEXA). RESULTS: The fat mass of the normal weight subjects was significantly lower than that of the overweight, which in turn was lower than that of the obese participants. Serum 25OHD levels increased significantly in all groups, peaking 1 week after the cholecalciferol load. Peak serum 25OHD levels were lower the higher the individuals' BMI. After peaking, the 25OHD levels gradually decreased, following a significantly different trend in the three groups. The slope was similar for the overweight and obese, declining significantly more slowly than in the normal weight group. In the sample as a whole, there was a weakly significant negative correlation between fat mass and baseline 25OHD level, while this correlation became strongly significant at all time points after cholecalciferol loading. CONCLUSIONS: The lower peak 25OHD levels seen in the obese and overweight is probably due to the cholecalciferol load being distributed in a larger body volume. The longer persistence of 25OHD in their serum could be due to both their larger body volume and a slower release into the circulation of the vitamin D stored in their adipose tissue.

Adrenal nodules in patients with Cushing's disease: prevalence, clinical significance and follow-up.

UNLABELLED: Adrenal glands in Cushing's disease (CD) range from normal to showing diffuse enlargement in most cases. The finding of nodular lesions has been reported, but information about prevalence and evolution is described in few reports. AIM: To investigate the prevalence of nodular adrenal glands in patients with CD and assess its evolution after disease remission. SUBJECTS AND METHODS: We assessed 41 CD patients' abdominal computed tomography (CT) scans obtained during the active phase of the disease and evaluated the dynamics of ACTH and cortisol secretion. CT was repeated after disease remission in patients with adrenal nodules. RESULTS: Fifteen of 41 patients had nodular and the remaining 26 had normal or enlarged adrenal glands. Patients with nodules were older (45.1 ± 8.8 vs 36.9 ± 12.7 yr; p=0.03) and had longer-standing disease (57.3 ± 56.9 vs 32.9 ± 29.1 months; p=0.05) than patients with normal/enlarged adrenal glands. ACTH (45.4 ± 21.3 vs 70.5 ± 39.1 pg/ml; p=0.04) and urinary free cortisol levels (606.1 ± 512.3 vs 301.0 ± 224.7 µg/day, p=0.01) were significantly lower in patients with adrenal nodules while there were no differences between the groups in terms of dynamic tests results. Post-operative follow-up showed regression or shrinkage of the nodules in 8 out of 10 patients in disease remission. CONCLUSIONS: We found that adrenal nodular glands are a frequent finding in CD in particular in older patients and in those with a longerstanding disease. Nevertheless, a high percentage of nodules regression or shrinking was evidenced in our series after disease remission.

The usefulness of combined biochemical tests in the diagnosis of Cushing's disease with negative pituitary magnetic resonance imaging.

OBJECTIVE: The etiological diagnosis of ACTH-dependent Cushing's syndrome is often a problem. In fact, no endocrine or radiological examination can conclusively distinguish the ectopic from the pituitary source of disease. The aim of our study was to evaluate the role of stimulation and suppression endocrine tests in the diagnostic and therapeutic approach of patients with Cushing's disease (CD) and negative pituitary magnetic resonance imaging (MRI), considering their post-surgical outcome in comparison with patients with CD and positive MRI. PATIENTS AND METHODS: We retrospectively analyzed 31 patients (25 women and 6 men, median age 40 +/- 15 years) with a confirmed diagnosis of CD who underwent transsphenoidal pituitary surgery by the same neurosurgeon between 2001 and 2005. Preoperative endocrine assessment included corticotropin-releasing hormone (CRH), desmopressin (dDAVP), and overnight 8 mg dexamethasone suppression tests (8-DST) in all patients. Fifteen patients had a normal pituitary MRI and sixteen had a clearly evident pituitary microadenoma. Bilateral inferior petrosal sinus sampling (BIPSS) was performed in patients with discordant biochemical results or with signs and symptoms highly suggestive of an ectopic source of ACTH. Post-surgical median follow-up was 38.4 +/- 22.0 months. RESULTS: Among patients with negative MRI, 60% had concordant positive endocrine tests and underwent neurosurgery without other examinations. BIPSS was performed in three other patients prompted by discordant endocrine tests (negative dDAVP) and in two patients with clinical suspicion of ectopic disease. Among patients with positive MRI, 87% underwent neurosurgery without BIPSS that was performed in two patients because of negative concomitant response to dDAVP and CRH tests. A pituitary adenoma, confirmed by pathological examination, was found in 40 and 81% of patients with negative and positive MRI respectively (P<0.05), corticotroph hyperplasia resulted more frequent in the group with negative MRI. Remission rate was not different between patients with negative and positive MRI (73 and 75% respectively; P=0.61) and between patients with negative MRI who did not undergo BIPSS and patients with positive MRI (P=0.56). The recurrence rate was also similar between groups (P=0.64), but higher, although not statistically different (P=0.07) in patients with corticotroph hyperplasia at histology. CONCLUSIONS: An accurate evaluation of presurgical endocrine tests results enabled us to reduce the number of BIPSS in patients with a negative MRI without any fallout on their post-surgical outcome. In the hands of an expert pituitary surgeon, the outcome after surgeryand the subsequent recurrence rate are much the same in patients with negative or positive MRI.