Effect of thyroxine and prednisolone and the exogenous RNA induced by them on the proliferation of cells

: As demonstrate experiments performed on cells of the primary culture of the newborn rat kidney, injection of thyroxin stimulates, and addition of prednisolone inhibits the proliferative activity of the cells in the culture. At a combined and simultaneous administration of these two hormones, as well as at injection of thyroxin 2 h before prednisolone, the thyroxin program, stimulating the cell proliferation is expressed. When thyroxin is administered 2 h after prednisolone, during first 12 h the prednisolone program is expressed, and then the proliferative activity of the culture returns to the initial level. At the cooperative action of oppositely directed factors for realization of the cell proliferative program, an essential role play the time factor and lag-period duration for each of the hormones interacting. Exogenic RNAs, obtained from the kidneys of the rats, to whom thyroxin or prednisolone have been injected, when they (RNAs) are injected into the culture, they produce effects, similar to those that are noted at injecting these hormones into the incubation medium. Thus, injection of the hormones to rats, results in formation, by the cells of the organ, induced RNAs, capable to transfer a hormonal signal and produce a hormone-like effect at regulation of the proliferative activity of the cell culture in the obtained exogenic RNA from the organ-donor.