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The influence of glucosamine, galactosamine, glucuronic acid and of some derivatives of these compounds on mucopolysaccharide metabolism and on protein metabolism of primary fibroblast monolayer cultures was studied. Glucosamine, glucosamine · HC1, glucosamine · HJ and glucosamine sulfate (in concentrations of 100 µg/ml each) caused a considerable, statistically highly significant increase of the secretion of mucopolysaccharides by the fibroblasts. N-Acetylglucosamine and N-acetylgalactosamine were effective too, though to a lesser degree. Glucuronic acid was without any influence on mucopolysaccharide production. The protein content of the cultures was not affected by the 7 compounds mentioned so far in concentrations of up to 100 µg/ml. Galactosamine and betaineglucuronate induced a certain depression of a mucopolysaccharide production and simultaneously a decrease of the cellular protein content.

The isolated frog's sartorius muscle has been used extensively for studies on the nature of the resting and action potential. The ionic basis of these phenomena is now well established. Conway (1957) and Ussing (1960) have reviewed the extensive evidence underlying these ideas. While it is known that the resting potential of muscle fibres kept in Ringer's solution can remain at normal levels for up to 7 hr (Woodbury, 1958), it is likewise known that muscles kept in Ringer's solution can change their ionic composition considerably. Boyle & Conway (1941) and Carey & Conway (1954) have presented extensive evidence concerning the loss of potassium ions and gain of sodium and chloride ions of muscles soaked in various solutions (see also the general discussion by Ussing, 1960, pp. 84-95).There have been many experiments based on the original experiments of Steinbach (1940) where frog muscles were soaked in potassium-deficient solutions at low temperatures for many hours (usually overnight), and the gain of potassium and loss of sodium were followed when the muscles were replaced in various solutions at room temperature. These soaking experiments have been primarily directed towards an understanding of the ionic pumping mechanisms for sodium and potassium (vide Conway, 1957, andConway, 1960, for a discussion of these aspects).Despite the large number of experiments on frog muscle resting potential or ionic composition changes, comparatively little attention has been given to the relation between these two aspects in muscles left in a simple Ringer-type solution. The necessity for this information became apparent when studies were commenced on the action of such drugs as local anaesthetics and cardiac glycosides on the muscle membrane. These drugs have a very slow effect on the resting potential, and in order to follow the influence of these drugs on the resting potential and ionic movements across the muscle membrane it became necessary to establish what was happening

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