Type II (non-insulin-dependent) diabetes mellitus is a common, age-related, multifactorial disease [1,2]. Although still debated, it seems that the primary defect in most subjects developing Type II diabetes involves resistance to insulin action in muscle or liver or in both which initially is compensated for by increased insulin secretion. When in addition insulin production becomes impaired (ªbeta-cell exhaustionº), however, glucose intolerance or overt diabetes may develop [3±5]. Therefore, factors inhibiting insulin production might promote progression to overt diabetes in subjects with insulin resistance. Islet amy- Diabetologia (1999) Abstract Aims/hypothesis. Type II (non-insulin-dependent) diabetes mellitus is a multifactorial disease in which pancreatic islet amyloid is a characteristic histopathological finding. Islet amyloid fibrils consist of the beta-cell protein ªislet amyloid polypeptideº (IAPP)/ªamylinº. Unlike human IAPP (hIAPP), mouse IAPP cannot form amyloid. In previously generated transgenic mice, high expression of hIAPP as such did not induce islet amyloid formation. To further explore the potential diabetogenic role of amyloidogenic IAPP, we introduced a diabetogenic trait (ªobº mutation) in hIAPP transgenic mice. Methods. Plasma concentrations of IAPP, insulin and glucose were determined at 3.5 (t1), 6 (t2), and 16±19 months of age (t3). At t3, the mice were killed and the pancreas was analysed (immuno)histochemically.Results. In non-transgenic ob/ob mice, insulin resistance caused a compensatory increase in insulin production, normalizing the initial hyperglycaemia. In transgenic ob/ob mice, concurrent increase in hIAPP production resulted in extensive islet amyloid formation (more often and more extensive than in transgenic non-ob/ob mice), insulin insufficiency and persistent hyperglycaemia: At t3, plasma insulin levels in transgenic ob/ob mice with amyloid were fourfold lower than in non-transgenic ob/ob mice (p < 0.05), and plasma glucose concentrations in transgenic ob/ ob mice were almost twofold higher (p < 0.05). In addition, the degree of islet amyloid formation in ob/ob mice was positively correlated to the glucose:insulin ratio (r s = 0.53, p < 0.05). Conclusion/interpretation. Islet amyloid is a secondary diabetogenic factor which can be both a consequence of insulin resistance and a cause of insulin insufficiency. [Diabetologia (1999)

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Abstract. Two patients with hyponatraemia resulting from an inappropriate ADH secretion syndrome had low serum values and elevated clearances of uric acid. All the values returned to normal after fluid restriction. The same changes in uric acid clearance and serum level were seen when this syndrome was experimentally induced in five normal subjects.

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