What is Metabolism?
Metabolism describes all the chemical reactions that are involved in maintaining the living state of cells and organisms. It serves three main purposes of life, which are –

1. The conversion of energy in food, to the energy available to run cellular processes.

2. The conversion of food into two building blocks of proteins, lipids, nucleic acids, and carbohydrates.

3. The elimination of metabolic wastes.

All these processes allow organisms to grow and reproduce, maintain their structures, and respond to their environment.

What is an Endocrine system?

The endocrine system consists of feedback loops of hormones that act as chemical messengers released by the internal glands of an organism directly into the bloodstream and regulate distant target organs. These hormones govern nearly all the processes of our body including metabolism, growth and development, emotions, moods, sexual function, and sleep. The endocrine system comprises glands like – Hypothalamus, pituitary, thyroid, adrenal glands, pancreas, parathyroid, pineal, ovaries, and testes.

Ayurvedic perspective on Endocrine system and Metabolism:

The building block of Ayurvedic theory is Tridoshas namely – Vata, Pitta, and Kapha Dosha. Tridoshas are responsible for the maintenance of health by controlling all the physiological and psychological processes of the body. The cause of any disease is due to the disturbance in the equilibrium state of these Doshas. According to modern science, almost all processes are governed by hormones; and according to Ayurveda, all the processes are governed by Tridoshas. So let’s now view their (Tridoshas and hormones) correlations in different processes within the body.

1. Function of Hypophysis:

The growth and activity of thyroid gland are influenced by the thyrotropic hormone. In the ayurvedic text, Kapha Dosha is responsible for growth.

This hormone also influences the activity of the thyroid gland. According to Charaka the functions of Vata dosha as Pravartaka Cheshtana (activity pertaining to the thyroid gland) by the influence of thyroid-stimulating hormone, is similar to Vata Dosha.

The thyrotropic hormone also secretes a proteolytic enzyme that converts thyroglobulin and thyroxine. In the ayurvedic text, this transformation is the function of Pitta dosha and it is possible via the digestion process through Agni only.

Adrenocorticotropic hormones regulate the growth and activity of the adrenal cortex and thyrotropic hormones with follicle-stimulating hormones taking part in the development of the thyroid gland graafian follicle. Both these activities are similar to the activity of Kapha Dosha as mentioned in Ayurveda.

The size of an individual is determined by growth hormones. Upachaya being the function of Kapha Dosha, the function of growth hormone can be compared with the function of Kapha. The growth of the body is proper when dhaatu are properly nourished. Thus, the development and growth of the body depend on Dhatvaagni and Bhutagni. Both these forms of Agni depend on the digestive fire Jatharagni, so the growth hormone can be regarded as Pitta.

2. The function of Hypophysis:
The urine output is controlled by antidiuretic hormone. Jalamahabhuta Pradhana is the term for urination in ayurvedic text and is the substance of Kapha Dosha. Under normal functioning, Vata dosha is responsible for absorption and vigorous uterine contraction, thus expelling the fetus and placenta.

3. Functions of the Thyroid gland:
The thyroxine hormone of the thyroid gland can be correlated with the function of Pitta dosha. Pitta is responsible for the entire metabolism process within the body. The basal metabolic rate is regulated by Pitta, whose release is essential and requires heat and energy in the body. The motion of Dhatvaagni and Bhutagni is attained by Pachaka Pitta. Also, the conversion of one thing into another is an exclusive property of Pitta. Thus, thyroid gland secretions are of the nature of Pitta.

4. Functions of the parathyroid gland:
The rate of calcium phosphate is regulated by the parathyroid gland. This regulation is with respect to the metabolism of calcium and phosphate in the body, which can be regulated by Pitta. Also to exercise its influence on the factors responsible for the regulation of the metabolism of calcium phosphate rate is regulated by Vata Dosha and at times stabilizers the other two doshas by implication of all Dhatvaagni and Bhutagni. Thus, it can be said that the functions of hormones of the parathyroid gland are similar to the functioning of Vata Dosha.

5. Functions of Pancreas:
The carbohydrate metabolism is regulated by insulin and hormones of the adrenal cortex and is one of the functions of Vata. Hexokinase enzyme is stimulated by insulin for the conversion of glucose into glycogen, while the hormone of the adrenal cortex inhibits the function of hexokinase enzyme, as, if the stimulation of insulin is more there will be no control over it, and will produce more disorders. Thursday the proportion of insulin and adrenal cortex hormones should be at a level that the conversion of glucose into glycogen may happen properly. Hence the normal physiological function depends on Vata, as it regulates carbohydrate metabolism.

6. Functions of the adrenal gland:
The adrenal cortex hormone also stimulates sodium and potassium metabolism. As these elements are panchmahabhuta, this can be attributed to Bhutagni Paka. The adrenal gland also controls the function of intestinal activity which pertains to samana vata of the ayurvedic context. Further, simulation of the whole body in an emergency can be attributed to Pitta, because in emergency time intelligence is required, which is a function of sadhaka Pitta.

7. Functions of Gonads:
The function of the ovary can be related to Vata. The main function of ovarian hormones is to
regulate the menstrual cycle, and the same is of Apana Vata.

The testicular hormones are responsible for the development of sexual organs. This can be regarded as the function of shukra dhatu and its formation in Pitta and the development of Shukra vaha srotas by Vata.

The above correlation between Doshas and the endocrine system lays a context for how Ayurveda explains every conversion of the body, as a virtue of Doshas. As every conversion within the body is regarded as metabolism, and the endocrine system is responsible for the same – so are the Doshas.