Frog skin osmotic permeability—Effect of acute temperature changein vivo andin vitro

Temperature has a pronounced effect on the osmotic water permeability of bothin vivo andin vitro frog skin (Table 1). After an acute temperature change of 10°C, between 5°C and 15°C, thein vivo response can be divided into two stages (Fig. 1 and 2). The first stage is seen onlyin vivo and therefore may involve a mechanism at the whole animal level of organization. The second stage is seen bothin vivo andin vitro (Fig. 3) and can be explained by an effect at the tissue level of organization. An acute temperature decrease causes a significant decrease in the osmotic concentration of the plasma within one hr (Fig. 4). There is no significant salt-linked water flowin vivo in the presence of 150–200 mOsm osmotic gradient (Table 2).