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A frequent coincidence of perinuclear microtubules and chromatin strands at nuclear membrane level was observed in spermatids ofChorthippus apicalis andOedipoda coerulescens. More developed spermatids also show apparent continuity between these chromatin strands and microtubules. We would suggest the importance of this relationship in the arrangement adopted by these strands.

The metabolic effects of glucagon and glucagon plus insulin on the isolated rat livers perfused with 10 mM sodium L‐lactate as substrate were studied. Glucagon stimulated gluconeogenesis, ketogenesis and ureogenesis at the concentration used of 2.1 nM. The addition of insulin to give a glucagon‐to‐insulin ratio of 0.2 reversed all the glucagon effects. The glucagon enhancement of gluconeogenesis was accompanied by a rise in the cytosolic and mitochondrial state of reduction of the NAD system and a fall in the [ATP]/[ADP] ratio. The analysis of the intermediary metabolite concentrations suggested, as possible sites of glucagon action, the steps between pyruvate and phosphoenolpyruvate as well as the reactions catalyzed by phosphofructokinase and/or fructose bisphosphatase. All the changes in metabolite contents were abolished when insulin was present. Glucagon increased the intramitochondrial concentration of all the metabolites, whose intracellular distribution was calculated. The finding of a significant rise in the calculated intramitochondrial concentration of oxaloacetate points to pyruvate carboxylation as an important site of glucagon interaction with the gluconeogenic pathway. A primary event in the glucagon action redistributing intracellular metabolites seems to be the mitochondrial entry of malate. The possibility is discussed that the changes in metabolite cellular distribution were brought about by the increased cellular state of reduction caused by the hormone.

The synthesis of proteins with affinity for DNA has been studied in clones of a Syrian hamster cell line (NIL) and subclones of this line transformed by polyoma virus (NIL-Py) or hamster sarcoma virus (NIL-HSV). The results show that the synthesis of DNA-binding proteins in NIL and in its virus-transformed derivatives NIL-Py and NIL-HSV is very similar in exponentially growing cells, but in dense culture there is a very significant difference in the level of a protein (PS), which is much higher in the transformed lines than in untransformed NIL. The high levels of P8 in dense trans- formed cells have been observed in all the clones of trans- formed cells examined, indicating that this behavior of P8 is related to transformation and not simply due to a fortuitous clonal selection from the NIL. Experiments with synchronized cells indicate that the time of maximal P8 synthesis relative to cellular DNA synthesis in NIL-HSV precedes that ob- served in NIL cells. P8 has a molecular weight of 30,000 as determined by polyacrylamide gel electrophoresis in the pres- ence of sodium dodecyl sulfate and is present in large amounts in the transformed cells in dense culture, where it makes up 0.5 to 1% of the total soluble protein.