Who is this book aimed at?

This is an intermediate level book aimed at undergraduate and graduate students following human biology programmes who have a basic understanding of renal physiology.

Aim

The aim of this open educational resource is to show you how something called the clearance approach can be used to examine renal function in vivo, with an emphasis on human data. We will cover the different calculations used in clearance approaches, and then use these in a formative, sample exercise.

Why is the clearance approach useful?

Investigating renal function requires the use of a wide range of experimental approaches.  In the research laboratory, many studies utilise freshly isolated nephrons and renal epithelial cells,  cultured cells or use expression systems to evaluate aspects of renal physiology and pathophysiology (in vitro experiments).  However, there is also a need to study function in the whole kidney in vivo, where neuronal and hormonal regulation of the kidney is intact, and the different sections of the structural unit of the kidney, the nephron, can influence each other.  The clearance approach allows you to complete this evaluation of whole renal function.

In addition, as well as being invaluable for renal research, the clearance approach also has a direct and important clinical relevance, as it is used to investigate changes in renal function in a variety of renal conditions.

Objectives

By the end of the resource, and completion of the sample exercises, you should be able to:

• Calculate glomerular filtration rate (GFR).
• Calculate the rates of filtration, reabsorption and excretion of water, electrolytes and solutes.
• Calculate the fractional reabsorption and excretion of water, electrolytes and solutes.
• Evaluate the impact of a diuretic on renal function.

This resource will take you through some basic renal physiology (to remind you about the background), and then cover the steps needed to use the clearance approach to  investigate renal function. We will look at the different calculations used in the clearance technique and review the requirement for using standard units.  The resource will finish with an opportunity for you to complete some calculations looking at the response to a diuretic, and review how the clearance data can be used to explain the impact of the diuretic.

Peer review

With thanks to Daniela Cacciabue and Gordon Cooper for their peer review of the book.