When Sarcoma 37 ascites cells were incubated in the presence of actinomycin D, protein synthesis was inhibited. The inhibitory effect could be prevented or relieved by glucose or by a variety of glycolyzable substrates. The inhibitory effect was independent of the concentration of the labeled amino acid precursor. Under conditions inhibitory to protein synthesis, no significant inhibition of re...

This study is concerned with the fate of the nucleolar contents, particularly nucleolar RNA, during mitosis Mitotic cells harvested from monolayer cultures of Chinese hamster embryonal cells, KB6 (human) cells, or L929 (mouse) cells were allowed to proceed into interphase in the presence or absence (control) of 0.04-0 08 microg/ml of actinomycin D, a concentration which preferentially inhibits ...

The effects of two different inhibitors of rat liver RNA synthesis, actinomycin D and ethionine, upon liver RNA metabolism have been studied and compared. Whereas ethionine administration leads to a relatively slow loss of about 30% of total nuclear RNA over a period of 12 to 16 hours involving the molecular species representative of the total pool, the administration of actinomycin D is follow...

1. The concentrations of liver glycogen and plasma d-glucose were measured in caesarian-delivered newborn rats at time-intervals up to 3h after delivery after treatment of the neonatal rats with glucagon, dibutyryl cyclic AMP, cortisol or cortisol+dibutyryl cyclic AMP. Glycogenolysis was promoted by glucagon or dibutyryl cyclic AMP in the third hour after birth but not at earlier times. Cortiso...