Alcohol consumption alters insulin secretion and cardiac autonomic activity.

BACKGROUND: Alcohol may have a cardioprotective effect. One possible mechanism is by modifying insulin resistance/secretion. The aims of this study were: (i) to examine the effect of short-term alcohol consumption on the metabolic control of glucose tolerance; (ii) to study the influence of short-term alcohol consumption on cardiac autonomic activity using spectral analysis of heart rate variability. METHODS: Twenty-one healthy subjects, in a randomized crossover design, either received three units of ethanol daily for 1 week or abstained from ethanol. The control of glucose tolerance was assessed using the intravenous glucose tolerance test with minimal modelling. RESULTS: There was no difference in fasting glucose, fasting insulin or insulin sensitivity between the two groups. Alcohol showed a lower insulin first phase insulin response (no alcohol 659.0 +/- 394.1 SD, alcohol 535.2 +/- 309.1) pmol L-1 min-1, P = 0.027). There was no difference in heart rate or blood pressure but a significant difference in the ratio of high to low frequency spectral power of heart rate variability; (no alcohol 4.55 +/- 3.78, alcohol 8.16 +/- 6.77, P = 0.033). This suggests decreased sympathetic and/or increased vagal modulation of heart rate in the alcohol group. CONCLUSION: The finding of no difference in insulin sensitivity between the two groups contrasts with, but does not entirely contradict, the results of previous epidemiological studies--perhaps suggesting that longer term changes such as liver enzyme induction may be important. The difference in insulin secretion questions the validity of previous studies of the influence of alcohol on insulin sensitivity, where insulin levels were used as a surrogate for insulin resistance.

Inflammatory hypophysitis - the spectrum of disease.

BACKGROUND: Inflammatory conditions of the pituitary are rare and consequently there are a number of single case reports of this condition but few reports of series. The condition is often divided into lymphocytic and granulomatous hypophysitis and it has been suggested that these two conditions represent the ends of a spectrum of disease. METHOD: We present our experience with 14 cases of this condition, correlating the presenting symptoms with the neuroradiology, surgical findings and subsequent histology. FINDINGS: The subjects (11 female 3 male) ranged in age from 13 to 64 years. Final histopathological diagnoses included 5 cases of lymphocytic hypophysitis, 4 cases of Rathke's pouch cyst with granulomatous response, 2 cases of granulomatous hypophysitis and 1 case with an inflammatory process that did not fit the current classification. Two subjects did not undergo surgery. Headache was a presenting feature in 11 of 14 cases and fever in 3 of 14 cases. Length of symptoms prior to presentation varied from acute onset to 9 years. One case of lymphocytic hypophysitis was associated with pregnancy. Evidence of hypopituitarism was present in 9 of 10 subjects assessed preoperatively. Preoperative radiology showed three patterns of disease: A cystic appearance was common with low signal content on MRI T1 weighting with an enhancing ring and a thickened enhancing stalk (5 patients). 4 patients showed a solid enhancing mass. A third group (2 patients) showed cysts with high signal content on T1 weighting - both of these were Rathke's cysts on histology. INTERPRETATION: Overall there were no striking features in the clinical presentation to distinguish pituitary inflammation from pituitary adenoma. The prognosis was generally good.