Combined in vivo and in vitro approaches to analysis of renal tubule function

The study of renal tubule function obtained its first impulse with whole kidney approaches, such as the clearance technique, and is presently centered on cellular analysis involving intracellular ion activities and on molecular studies describing the structure of transporter molecules and the function of their subunits and constitutional building blocks as well as their distribution along the nephron and within individual cells. Between these extremes a number of successful techniques have dominated the field, including the micropuncture methods which were pioneered by Richards, Walker and others in the late 1920s and 1930s, and were revived and perfectioned in the following decades leading to complex in vivo and in vitro micromethods that for an important period of time have been the center of scientific progress in this area. In the present paper, some of the methods in this field are shortly reviewed, specifically from the point of view of acid-base physiology applied to the renal tubule.