Refrigerated Storage of Oviductal Oocytes into Live Females Common Frog <i>Rana temporaria</i> from 1 to 70 Days

It has been shown for the first time that females of the common frog R. temporaria, kept in a refrigerator at a temperature of +4°C (below the optimum for spawning), can retain ovulated oocytes in the oviducts for more than 2 months, which at the same time retain their physiological usefulness. After 70 days of such storage, 75.8 ± 8.1% of the oocytes were capable of fertilization. Of these, 74.8 ± 8.4% of larvae developed to hatch. It has been suggested that ovulated common frog oocytes are in the oviduct in a state of reduced metabolism due to the presence of hypometabolic agents in them. The prospects for refrigerated storage of unfertilized oocytes outside the body of living frogs are considered, indicating two important factors. Firstly, the activity of water in the storage medium should be equal to the activity of water in the jelly coats of the oocyte to prevent its swelling, and secondly, the medium should not contain low molecular weight dissolved components that can penetrate into the jelly coats.