MEIOSIS INDUCING INTERACTION BETWEEN GERM-CELLS AND RETE CELLS IN FETAL MOUSE GONAD

During the period of the sexual differentiation of the gonads of the mouse the rete system of the 2 sexes secretes a substance, the MIS, which induces in the germinal cells the appearing of the preleptotene stage of chromosomic condensation. In the testicle only the gonocytes not enveloped in the testicular cords and placed near to the rete begin the meiotic prophase. The gonocytes in the testicular cords do not enter into the meiotic prophase. It is suggested that a substance obstructing the entry into meiosis, the MPS, is present in the testicular cords and that the isolation of the gonocytes in the cords where the MPS is located, prevents the action of the MIS. In the ovary the MPS might be responsible for the arrest of the meiosis when the ovocyte is included in the follicle.