We re-examined, in the context of modern practice, plasma insulin and stress hormone concentrations in patients admitted to hospital with acute coronary syndromes. Venous blood sampling was carried out prior to anti-thrombotic therapy in 148 patients with myocardial infarction (MI); 76 patients with unstable angina (UA) pectoris were also studied, together with 27 patients with non-cardiac chest pain (NCP). There were significant progressive increases in the concentrations of catecholamines, cortisol, glucose and insulin from NCP to UA to MI patients. Hyperglycaemia (glucose > 8 mmol/l) was present in over 50% of MI patients. The plasma cortisol and insulin levels were both significantly positively correlated with the glucose concentration on admission. Only the cortisol concentration was correlated with peak cardiac enzyme levels. The glucose and insulin concentrations on admission in 141 MI and UA patients were related to insulin resistance, as judged from subsequent insulin and glucose concentrations measured while fasting and during a glucose tolerance test. The product of admission insulin×glucose (divided by 25; the admission insulin-resistance index, or AIRI) was significantly correlated with indices of insulin resistance, and was significantly higher (approximately double) in the MI group (7.81±0.76) and the UA group (6.88±1.19) than in the control NCP group (3.59±0.06; Kuskul–Wallis: P = 0.0001), implying that the insulin levels in the first two groups were approximately twice as high as is appropriate for the glucose levels. The ethnic origin of 20% of the patients was the Indian subcontinent; admission insulin and glucose levels in this subgroup were higher than in the non-Asians across all the groups with chest pain. Cortisol was the only stress hormone that was raised in proportion to the size of the infarct, and is a likely partial cause of the elevation in blood glucose. The high insulin levels were related to the prevalence of insulin resistance, and this was particularly important in the Asian subgroup presenting with MI and UA. Thus it appears feasible to identify acute coronary syndrome patients who are insulin-resistant at a time (on admission) when alternative early therapeutic strategies can be instituted.

1. The plasma's ability to stimulate guinea-pig renal glucose 6-phosphate dehydrogenase (G6PD) in vitro was measured by a cytochemical technique in 23 normotensive subjects and 19 patients with hypertension, all of whom were studied on their normal sodium intake. The ability of plasma to stimulate renal G6PD was significantly ( P < 0.001) increased in the hypertensive patients (mean 195 ± 52 units/ml) compared with the normotensive subjects (mean 22.2 ± 5.8 units/ml). In all 42 individuals, there was a significant correlation between diastolic pressure and the ability of plasma to stimulate G6PD ( r = 0.69 P < 0.001). 2. The ability of plasma to stimulate G6PD was greatest in the hypertensive patients with values of plasma renin activity below the normal range. In the normotensive subjects the ability of plasma to stimulate G6PD was significantly greater in the older subjects. 3. As the ability of plasma to stimulate G6PD reflects its ability to inhibit Na + ,K + -dependent ATPase, these results suggest that patients with essential hypertension have an increase in a circulating inhibitor of Na + ,K + -ATPase. The results support the hypothesis that a rise in a circulating sodium transport inhibitor may, in part, be responsible for the rise in blood pressure in essential hypertension, and may form the link between salt intake, abnormalities of sodium transport and a rise in blood pressure.

1. Plasma 25-hydroxy-vitamin D concentration was measured in 40 normal subjects, 19 patients with terminal renal failure, 137 patients who had been on dialysis up to 11 years and in 17 renal transplant patients. 2. The mean plasma concentration of 25-hydroxy-vitamin D was below normal in patients with terminal renal failure and in patients who had been on maintenance haemodialysis for less than 1 year. The mean concentration in patients who had been on dialysis for more than 1 year and in renal transplant patients was normal. 3. The seasonal variation of plasma 25-hydroxy-vitamin D concentration found in the 58 patients on maintenance haemodialysis for more than 2 years is similar to that reported in normal subjects.