In Indian colloquial language, the word ‘sugar’ has several alternatives – mostly, it means the commodity used in cooking or refers to a disease. Despite the misnomer, Indian society is familiar with the danger posed by this disease often referred to as ‘sugar’. The formal terminology, however, is DIABETES.
Diabetes is a condition wherein the GLUCOSE (the primary form of sugar) is too high in the blood. In the body, conditions of the extremities are detrimental to health. The appropriate level of each molecule in the body is essential to maintain HOMEOSTASIS. Homeostasis is the stability between the various aspects of the body.
Diabetes is one of the most common diseases in the world and is categorised into several types because of its occurrence. However, the treatment of diabetes is common knowledge. Since there is an increase of the sugar glucose in the blood, a condition HYPERGLYCAEMIA is observed.
The standard procedure is to inject a HORMONE into the person’s body SUBCUTANEOUSLY. Subcutaneously is a term used to describe injection into the fat layer under the skin. When the hormone does its action, the level of sugar come within the normal range. However, the administration of the drug must be done with care since HYPOGLYCEMIA must be avoided at all costs.
Hypoglycaemia is the condition where the blood sugar level drops below the normal range. Since the body relies on glucose to obtain energy for every process, hypoglycaemia is a damaging condition. Statistics say that diabetics tend to die of hypoglycaemia than hyperglycaemia. Thus, the administration of the drug must be precise.
What is the mode of action of insulin?
The hormone which is injected into diabetics is called INSULIN. Hormones are chemical messengers of the body and hence, when insulin is injected, it issues a message to lower the blood sugar level. The chemical message inhibits glucose production and its release by the liver. It also prepares the skeletal muscles and fat cells to take up the excess glucose in the blood. When it is done with its action, the blood glucose level is stabilised.
Insulin is normally produced in the PANCREAS to help in the metabolism and uptake of sugar in the blood. Owing to several factors – several of which are still under study – a person starts producing insulin in lower levels. Thus, insulin has to be administered externally.
However, we know that most medicines or treatments we are subjected to involve oral administration. Capsules, tablets, and syrups are the most common delivery devices of the potent drug. One may wonder why commercial insulin – which has been around for several decades – cannot be taken orally.
Why can insulin not be administered orally?
While the research to enable oral insulin is underway, the primary limitation of consuming insulin lies in its nature. Insulin is a PEPTIDE hormone. Its biochemical structure is made up of AMINO ACIDS linked in a chain. Yet, its biochemical activity is that of a hormone. If insulin had behaved like a catalyst instead of a messenger, it would be called an ENZYME.
Enzymes are the primary impediment if one tries to consume insulin. Since the primary function of the mouth is to consume food, the entire DIGESTIVE TRACT is lined with enzymes. These enzymes are capable of breaking down carbohydrates, fats and most importantly, proteins. The mechanism of action of the enzymes is that the SUBSTRATE (the key molecule) is taken up by the enzyme and via a series of chemical reaction, is converted into a product.
Biomolecules such as carbohydrates, fats and proteins are usually broken down into its simpler constituents. Proteins are broken down to short peptides or amino acids. Thus, if someone were to consume insulin, the digestive enzymes in their OESOPHAGUS would breakdown the proteinaceous structure of the hormone into amino acids.
It then would be unable to regulate the blood sugar level since it would lose its activity in the oesophagus. Thus, currently, insulin needs to be injected into the subcutaneous levels of the skin for it to act on the blood sugar.
Why are people hoping for oral administration of insulin?
A diabetic person is usually administered insulin by themselves or a close one. Since the injection requires to be injected often, it is impractical to get it done by a doctor. Thus, diabetics or their close ones are trained by a professional to inject the hormone subcutaneously. Devices to administer insulin have greatly improved over the past two decades, however, the constant fear of inaccurate injection is persistent.
A tablet would be much more convenient in terms of administration and accuracy of the dose. It would also be less time-consuming and carry reduced risks. Hence, although the scientific community has not created consumable insulin, research is ongoing in these fields.