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The mineralogical distribution of Pd, Rh and Ru was determined in three small samples of disseminated ore from the layered Medevezhiy Ruchei Ni–Cu–platinum-group element mine, Noril'sk 1 layered intrusion, Siberia. The three samples were taken from a cross-section of the deposit ranging from the uppermost part of the picrite horizon (chill zone) through the main picrite horizon to the lower taxitic gabbro dolerites. Different microanalytical techniques were used to determine the major- and trace-element species as well as the abundance of major, minor and trace minerals. The results indicate that Pd is concentrated mostly in pentlandite and less in the platinum-group minerals (PGM). In the uppermost part of the picrite horizon about 67% of the Pd occurs in pentlandite, whereas only 30% occurs in the PGM. About two-thirds of the Rh is found in pyrrhotite; the second carrier of importance for Rh is pentlandite. The Ru distribution is more variable between the three samples, but about one-third of the Ru is carried by pentlandite, the remainder being distributed in variable amounts in pyrrhotite, chalcopyrite and pyrite. Knowledge of the platinumgroup element distribution is important for economic evaluation of the mineralization and for efficient metal recovery.

1. The activities of hexokinase (EC 2.7.1.1) and phosphofructokinase (EC 2.7.1.11) have been studied in homogenates of adipose tissue taken from human diabetics, fasting and control patients. 2. Three isoenzymes of hexokinase were observed with apparent Km values for glucose of 1.04 × 10-5 m, 2.6 × 10-4 m and 2.9 × 10-4 m, respectively. 3. No change in activity of hexokinase was found in adipose tissue of untreated diabetics (n = 22), treated diabetics (n = 13) or non-diabetic controls. However, fasting was associated with a decrease of approx. 40% in the activity of hexokinase in adipose tissue. 4. In contrast, there was a marked decrease in the activity of phosphofructokinase in adipose tissue from untreated diabetics (n = 24) which was restored to normal by either insulin therapy or treatment by hypoglycaemic drugs. 5. There was a negative correlation between the phosphofructokinase/hexokinase ratio in adipose tissue and the fasting blood glucose (P = 0.01) and the 2 h blood glucose (P = 0.03) after an oral glucose load (50 g). 6. The functional significance of the changes in enzyme activities is discussed in relation to the glucose intolerance of diabetes.

1. The ability of fat-free homogenates of human adipose tissue to incorporate [1-14C]palmitate into neutral lipid and long-chain fatty acyl-CoA has been studied. Homogenates readily incorporated [1-14C]palmitate into neutral lipid. Addition of l-glycerol 3-phosphate was required before synthesis of neutral lipid occurred whereas the system contained sufficient endogenous fatty acid for esterification with l-glycerol 3-phosphate. 2. Glucose, glucose 6-phosphate and fructose 1,6-diphosphate could replace l-glycerol 3-phosphate if the system was supplemented with NADH. The order of efficiency of each substrate to support esterification of [1-14C]palmitate was: l-glycerol 3-phosphate, fructose, 1,6-diphosphate, glucose 6-phosphate and glucose. 3. Factors known to alter the activity of phosphofructokinase (E.C.2.7.1.11) also altered the rates of incorporation of [1-14C]palmitate into neutral lipid. Thus citrate (10 mm) inhibited lipogenesis in this system when glucose 6-phosphate was used as initial substrate, but not when fructose 1,6-diphosphate was used. 3'5'-(cyclic)-AMP reversed the inhibition of lipogenesis by citrate. 4. Preparations of lipomata (benign tumours of adipose tissue) were found to be less sensitive to inhibition of lipogenesis by citrate (7 mm) but inhibition was observed at higher concentrations of citrate (21 mm). 3'5'-(cyclic)-AMP had no effect on lipogenesis in fat-free homogenates of lipomata in the presence of citrate (7 mm). 5. AMP (1·2 mm) inhibited the synthesis of long-chain fatty acyl-CoA without altering the rate of synthesis of neutral lipid from l-glycerol 3-phosphate. When the concentration of AMP was increased to 4 mm a concurrent decrease in lipid synthesis was observed.

1. The effects of glucose, glucose 6-phosphate, and l-glycerol 3-phosphate on the incorporation of [1-14C]palmitate into neutral lipid have been studied in homogenates of adipose tissue obtained from adult diabetics and control patients. In the diabetic, glucose, glucose 6-phosphate and l-glycerol 3-phosphate supported incorporation of 19, 27 and 62% of total counts respectively; whereas in paired non-diabetic controls the respective values were 78, 80 and 84%. 2. Confirmation of these results were provided by finding slower rates of conversion of [U-14C]glucose into phosphate esters in diabetic adipose tissue compared to paired non-diabetic controls. Rates were improved but not restored to normal by treatment of diabetic patients with insulin. 3. These results could not be explained on the basis of differences in isotope dilution in precursor pools or to the presence of raised levels of free fatty acids in diabetic tissue. 4. A group of latent diabetics showed a pattern of substrate utilization more like fully developed diabetes than non-diabetic controls. Rates of glucose phosphorylation were slower in latent diabetics than in paired controls. 5. Studies were also performed with homogenates of adipose tissue prepared from patients with Cushing's disease, obesity and pregnancy, these groups being predisposed to develop adult diabetes. 6. In Cushing's disease (eight patients) glucose, glucose 6-phosphate and l-glycerol 3-phosphate supported incorporation of 9 ± 1 (13), 19·2 ± 3·9 (10) and 23·2 ± 3·3 (9)% of total counts at 2 hr respectively; whereas in paired controls respective values were 19·7 ± 3·4 (10), 25·7 ± 2·8 (10) and 26·4 ± 2·9 (10)%. Support for these results was provided by finding slower rates (by about 50%) of conversion of [U-14C]glucose into phosphate esters in tissue from Cushing's disease compared to paired controls. 7. Ten obese patients with no clinical evidence of diabetes showed a pattern of substrate utilization more like diabetic adipose tissue; whereas another eight obese patients resembled their non-obese controls. 8. Adipose tissue from six pregnant patients (over 10 weeks) showed a diabetic pattern of substrate utilization; and confirmation was provided by rates of [U-14C]glucose conversion into phosphate esters (as counts × 10 min-1 mg protein-1 hr-1) of 929 ± 75 (5) in pregnancy versus 1386 ± 198 (5) in paired controls.