[Ca2+ exit from intracellular stores of growing and fully grown native and devitrified porcine oocytes]

The exit of Ca2+ from intracellular stores in growing and fully grown native and devitrified porcine oocytes stimulated by somatotropin and GTP was investigated using fluorescent dye chlortetracycline. In native as well as in the devitrified porcines oocytes, in their fully grown phase, joint action of somatotropin and GTP stimulated additional freeing of Ca2+ from intracellular stores, but during subsequent processing of the cell with nocodazole (a polymerization inhibitor of microtubules), additional exit of calcium did not occur. In the growing phase of native oocytes during the joint acting of somatotropin and GTP additional exit for Ca2+ from the intracellular stores did not occur. Join action of somatotropin and GTP on growing devitrified oocytes lead to the additional freeing of Ca2+ from intracellular stores. Injection of nocodazole inhibited the exit for calcium in growing devitrified oocytes treated with somatotropin and GTP. The data obtained points to the absence of difference of signal transduction mechanisms in growing and fully grown oocytes after devitrification.