Although mechanisms of insulin's regulation of glucose transport is not known, recent advances in biochemistry of insulin receptor and membrane structure and function clarify a certain aspect of transmitting insulin's signals. It is recently demonstrated that insulin's activation of glucose transport is modified by membrane fluidity, intracellular ATP levels, calcium ion, etc. These possible important factors are discussed individually to give a spectrum of various theories of mechanisms of insulin's activation of glucose transport. Through unknown mechanisms, insulin activates glucose transport by increasing Vmax of transport system rather than changing Km. At present time, it is not clear whether increased transmembrane mobility of glucose carrier or increased available binding sites for glucose contributes to this increased Vmax. Longterm regulation of glucose transport by insulin also relates with change in Vmax. The future investigation on microenvironment of plasma membrane surrounding insulin receptor and transporters seems to be important.

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Interaction of chemoreceptor membranes with chemical stimuli in lower organisms and higher animals is dealt with. The content is as follows: 1) Comparison of chemoreceptor function in various organisms 2) Caracteristics of receptor sites 3) Effect of changes in membrane lipid composition on receptor function 4) Changes in membrane fluidity in response to chemical stimuli 5) Reaction scheme for initial process of chemoreception 6) Role of membrane-bound Ca 7) Mechanism of membrane potential changes in response to chemical stimuli 7) Taste transduction mechanism

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The potential sensitive dye-related optical (absorption and/or fluorescence) signals have provided a new method for monitoring membrane potential and have already found many applications. In this article, the experimental basis of the optical method for monitoring of membrane potential was described, and its applications were subsequently summarized.

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Hemodialysis was used as an initial artificial kidney in 1913 and since then this system has been prevailing remarkably for renal failure treatment. However, new systems, hemoperfusion and hemofiltration, have been developed along with accelerated scientific progress. These three systems are based on diffusion, adsorption and filtration, respectively.
In terms of the solute-separation mechanism, the idea to regard device and patient as one united system is required. Therefore, two approaches have been adopted in our laboratory for the determination of solute-removal efficiency. One is in-vivo estimation by gel chromatography and amino acid analysis. The other is by mathematical simulation on solute-transfer with body-fluid compartment model. The compartment model has been improved by the use of routine clinical data. When solute-transfer can be simulated accurately by the model, most comfortable therapy for each patient will be decided under computer program.

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To analyze the biomembrane potential, Hodgkin-Katz equation is usually used, which has the same assumption as Goldman equation. In addition to the constant field assumption, they assume that ion concentration in membrane is directly proportional to ion concentration in bulk solution at bulk-membrane interface. In Hodgkin-Katz equation, the contributions to membrane potential from the interface are included in the permeability coefficient, P_κ, which is defined as B_κβ_κRT/F_AL, where B_κ is mobility of κ-th ion in membrane, Bκ is partition coefficient of κ-th ion and L is thickness of the membrane. So, the permeability coefficients play very important part on the study of membrane potential, but P_κ is used to be treated as a variable parameter determined by experimental data and theoretical study on P_κ has not been made so far. In this paper, P_κ is studied theoretically and it is pointed out that Hodgkin-Katz equation is quit equivalent to Goldman equation if the ratio of the partition coefficients are set as follows:
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where i, j show cations and a shows anions, z is charge of ions, gκ=γκM/b_κγ_κB, _bκ=exp (-Δμ_κ⁰/RT), γκ is activity coefficient of κ-th ion and suffixes M and B show membrane and bulk, respectively. ΔE_D1 and Δ_D2 show interfacial potentials at the interfaces 1 and 2, respectively. For a two ion system and a three ion system, the experimental conditions and methods are investigated in order to determine the value of parameters, B_κ and P_κ. It is also pointed out that the measured membrane potential can be separated into the diffusion potential and the interfacial potential by use of the value of β_κ.

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