Cytoplasmic manifestation of the nuclear membrane's hormone binding capacity during cell division.

Binding of insulin and thyrotropic hormone (TSH) to the nuclear membrane of Chang liver cells was demonstrated by qualitative and quantitative cytofluorimetry, which failed to substantiate a similar binding affinity for BSA. It appears that in the dividing cell the binding structures (receptors) of the nuclear membrane migrate in the cytoplasm together with the chromosomes by the end of the prophase and become reorganized in the nucleus around the telophase. The fluorescence which indicated binding also appeared in the midbody region during division of the two daughter cells. These experimental observations strongly suggest that, after cell division, only part of the nuclear membrane's receptor complement has to be resynthesized in the daughter cells, because the receptor number required by a single cell is conserved in cytoplasmic membrane details of nuclear membrane origin.