Introduction

Historically, animal research has led to many scientific breakthroughs, including elucidating the actions of our hormones. These discoveries were possible because the major hormone systems of most biological organisms are highly conserved and essential to healthy life. At the cellular and molecular level, humans are similar to other animals and this makes those animals good models to use in order to understand human biology and find new treatments for disease. Numerous medical discoveries have been made due to the use of animal models. For example, Frederick Banting and Charles best famously discovered insulin through their work with dogs; Rabbits helped Louis Pasteur to cure rabies; rhesus monkeys provided Jonas Salk with the polio vaccine; Albert Starr pioneered heart valve replacement surgery through his research on dogs; armadillos harbouring the leprosy bacteria led to the synthesis of leprosy antibiotics; and macaques were used in the process of developing effective drugs against the AIDS virus. Those against using animals in research say that because animals look and act differently to us, they cannot possibly represent the human body or mimic human diseases. But in fact animals are very similar in the genes that they carry and the hormones they produce and when we look at life at the cellular level in these animals, it seems remarkably similar. For example, we possess almost all the same hormones that a dog and a calf possess. The insulin that Banting extracted from the pancreas of his dogs and calves, when given to diabetic patients, was only effective as a treatment because the insulin molecule is so similar across species. But one might ask why not just experiment on cells grown in a test tube or on a culture plate? The answer is that huge numbers of experiments are carried out on cells that do not involve animals but these cells act in isolation and are not wholly representative of cells, organs and tissues that all act in concert within a living body. So in the end one has to transfer that knowledge gained from isolated cells into a whole living animal.

The importance of knockout mouse models

Animal models continue to play a vital role in scientific research; in particular, ‘transgenic animals’ that carry a foreign or over-expressed gene and ‘knockout mouse models’ in which the expression of a particular gene is removed. These models have led to a number of scientific breakthroughs and have allowed us to find out how different hormones, coded by a particular gene, can work in different parts of the body. For example, we now understand the role of leptin, secreted by fat, in controlling obesity and all the other problems associated with obesity including diabetes; the role of glucocorticoids in foetal programming; the importance of oestrogen in bone growth and the important role of the newly discovered hormone, kisspeptin, in controlling puberty and fertility. Various knockout mouse models have also led to the discovery of unexpected physical traits in the animal. This has then sparked the search for the (rare) human equivalents and, in doing so, opened up new areas of understanding of endocrine diseases with more general applications to the population.

Alternatives to animals

Animal models can’t always accurately predict the effects of a new drug in humans, but they often do. This is not to say that alternatives to animals should not be thoroughly investigated. In fact significant money, primarily provided by the National Centre for the 3 R’s - NC3R is invested for the replacement, refinement and reduction of animals in science. Furthermore, regulations and the ethical management of animal research are regularly re-assessed and refined, with the UK having very tough laws on these issues. Most scientific societies, including the Society for Endocrinology, highlight their importance and scientists constantly have to justify their requirements for the use of animals in their work. Encouragingly, the UK public’s perception of animal research is generally supportive. Nine out of ten people conditionally accept the idea of animal research and testing to some degree, with three in five accepting the idea unconditionally. About three quarters accept animal studies as long as they are for medical research purposes. Sometimes, however, small, vocal anti-vivisectionist groups dominate the media limelight to suggest these facts are otherwise. Recently, scientists have begun to fight back as they recognise the importance of greater public transparency of their work. Supporters of the need for animals in research have rallied under the Pro-Test banner and march annually in Oxford. Furthermore, there are various web-sites (such as Understanding Animal Research or Speaking of Research) that highlight how critical animal research is for furthering the biological goals of understanding life and curing disease. By aiding the development of a plethora of vaccines, surgery techniques, antibiotics, and drugs, animal research has saved countless lives. Alternatives are in development, but animals seem likely to be necessary to further scientific understanding and combat disease for the foreseeable future.