Diffusion of Lactic Acid Into and Out of the Voluntary Muscles of the Frog

Abstract

1. Observations on the diffusion of d‐lactate in and out of resting frog muscle during immersion in a Ringer's solution containing sodium d‐lactate show that only about one‐third of the muscle water appears to be involved in the diffusion process, the rest appearing to be shut off by membranes impermeable to lactate. These two portions of muscle have been termed “interspaces” and “cells” respectively. 2. In the fatigued muscle, the “interspaces” tend to disappear presumably due to a swelling of the “cells” on account of increased osinotic pressure within them. 3. In heat rigor, nearly the whole of the muscle water becomes available for the diffusion of lactate. 4. An excited state of the isolated muscle does not appear to render the membranes bounding the “cells” permeable to lactate. 5. The normal lactic acid concentration in the “cells” of isolated frog muscle is found to be lower than that in the “interspaces,” whether the frog is fresh or has been previously cooled or fatigued. Besides, the muscles in the body appear to maintain a relationship between their lactate concentration in these two fractions. The two values rise and fall together. 6. This relationship in the concentrations in the “cells” and “interspaces” suggests that although diffusion experiments with relaxed isolated muscles indicate complete separation of “cells” from “interspaces” in respect of lactate, the intact animal possesses some mechanism by which a relationship between the concentration of “cells” and “interspaces” is maintained. I am deeply indebted to Dr. P. Eggleton for help and guidance generously given. The expenses of this research were defrayed by a grant from the Moray Endowment Fund.

Intracellular pH and distribution of weak acids across cell membranes. A study of D‐ and L‐lactate and of DMO in rat diaphragm.

“…It is of interest to examine the early work of Ghaffar (1935) who equilibrated frog gastrocnemii at 00 C in Ringer, in which 0-50 mM-NaCl had been replaced by Na L-lactate. The muscle lactate concentration linearly related to that in the bath, with a ratio of distribution between muscle water and medium of about 0 3.…”

Diffusion of Iodide Into and Out of the Voluntary Muscles of the Frog

“…It has also been shown that in the case of the diffusion of some of these substances, for example, phosphate and lactate, only a fraction of the muscle water seems to be involved in the diffusion process, the rest appearing to be shut off by membranes impermeable to these ions [M. G. Eggleton, 1933;Ghaffar, 1935].…”

“…It has also been shown that in the case of the diffusion of some of these substances, for example, phosphate and lactate, only a fraction of the muscle water seems to be involved in the diffusion process, the rest appearing to be shut off by membranes impermeable to these ions [M. G. Eggleton, 1933;Ghaffar, 1935].This communication gives the results of certain observations in the diffusion of iodide (an ion not normally present in the animal body), through the frog muscle, and an attempt is made to correlate the low coefficient of diffusion in the case of living muscle to the inability of iodide to diffuse through a fraction of the muscle water. …”