No abstract

Rats trained on a diurnal controlled meal-feeding schedule and injected with a single dose of 3,5,3'-triiodothyronine (T3) failed to accumulate liver glycogen and incorporated less D-[6-3H]glucose into glycogen than normally observed during the feeding period. In the experimental group, the concentration of liver adenosine 3',5'-cyclic monophosphate (cAMP) did not fall during feeding and the pattern of activities of glycogen phosphorylase, glycogen synthase, and phosphorylase kinase remained conductive to glycogenolysis. Liver lysosomal alpha-glucosidase activity normally fell during feeding periods. After T3 treatment the activities of alpha-glucosidase and two lysosomal cathepsins (B1 and D) were elevated. The evidence suggests that T3 may induce both liver phosphorylase kinase and lysosomal alpha-glucosidase. This outcome of T3 excess, in concert with previously described T3-inducible systems, provides a plausible explanation for the failure of glycogen accumulation in this experimental model.

Magnesium was determined on aliquots of the same serum by atomic absorption and flame emission spectrophotometry, by Titan Yellow and Magon photometry, and by 8-hydroxy-quinoline and 8-hydroxy-quinoline-sulfonate fluorometry. Comparison is presented of reproducibility of results by the various methods and of the normal values obtained.

A rapid Tween 80 hydrolysis test for mycobacteria utilizing gas-liquid chromatography is described. The test requires 1 h of incubation followed by simple extraction and chromatography of nonderivatized oleic acid.

Gel filtration *.echniques of determining serum unbound calcium and magnesium have been studied. Dry and pre-swelled Sephadex (;-50 was used in procedures modelled on reported methods. Data are presented to support the conclusion that gel filtration, as a batch technique, remains unproved for the satisfactory quantitative estimation of unbound calcium and magnesium in serum.