Solubility in Isolated Bovine and Human Luteal Nuclei’

We have previously demonstrated that bovine and hwnan luteal nuclei contain hwnan chorionic gonad otropini luteinizing hormone (hCG/LII) receptors and that these gonadotropins can directly stimulate nuclear membrane enzyme activity (nucleoside triphosphatase) involved in messenger ribonucleic acid (nzRNA) transport from the nucleus to the cytoplasm. The present studies were undertaken to investigate the effect or hCG on chromatin solubility, reflecting perhaps synthesis and transport of RNA, in isolated bovine and human luteal nuclei. hCG increased chromatin solubility in a concentration-dependent manner. This hCG effect is either blocked or sub-stantially reduced by the addition of hCG antiserum; denatured hCG had no effect and cyclic adenosine 3’5’-monophosphwe could not mimic the hCG response. hCG had no effect on chromatin solubility in bovine liver or kidney nuclei and hormones other than hCG, human LII, or the subunit of hCG had no effect on chromatin solubility in bovine luteal nuclei, demonstrating the tissue and hormone specificity of the response. These findings further strengthen the concept of direct gonadotropin regulation of nuclear functions of luteal cells