Hormones are the chemical messengers of the body.
They regulate the body’s physiology based on the signals from the brain.
They transfer the signal directly to the respective organ or system for the changes to happen.
So they are like the messengers carrying a message from the brain to the other organs.
They are produced by the secretory cells of specific glands.
But they do not release them into the blood. Instead, the blood flows through these glands and carries them away.
So they are termed endocrine glands.
They regulate most of the body’s physiology and functions.
These hormones, if deficient or in excess, can lead to hormonal disorders.
These can have a harmful effect on health and physiology.
So how many hormones are there in the human body?
Below is the comprehensive list, along with their functions.
|Hormone||Function||Endocrine Gland secreting|
|Thyrotropin-releasing hormone (TRH)||Stimulates the thyroid gland to synthesize T3 & T4 hormones||Hypothalamus (HYP)|
|Corticotropin-releasing hormone (CRH)||Stimulates cortex of adrenal gland to secrete glucocorticoids and mineralocorticoids||(HYP)|
|Growth hormone-releasing hormone (GHRH)||Stimulates formation of growth hormone,||(HYP)|
|Growth hormone inhibitory hormone (GHIH) (somatostatin)||Inhibits release of growth hormone, TSH, insulin||(HYP)|
|Gonadotropin-releasing hormone (GnRH) or luteinizing hormone-releasing hormone.||Controls release of FSH, LH||(HYP)|
|Dopamine or prolactin-inhibiting factor (PIF)||Inhibits prolactin secretion.||(HYP)|
|Growth hormone||Stimulates growth of the body||Anterior pituitary (AP)|
|Thyroid-stimulating hormone (TSH)||Releases T3 & T4||(AP)|
|Adrenocorticotropic hormone (ACTH)||Stimulates the adrenal cortex to produce||(AP)|
|Prolactin||Stimulates milk formation||(AP)|
|Follicle-stimulating hormone (FSH)||Stimulates to form sperms in males and Ova in females.||(AP)|
|Luteinizing hormone (LH)||Formation of Ova in females & production of testosterone||(AP)|
|Antidiuretic hormone (ADH) (also called vasopressin)||Limit water expulsion by the kidney. It also constricts blood vessels and raises blood pressure||Posterior pituitary|
|Thyroxine (T4) and triiodothyronine (T3)||Regulates body metabolism and heat||Thyroid|
|Calcitonin||Reduces blood calcium by enhancing bone deposition, decreasing intestinal absorption, and expulsion by the kidney.||Thyroid|
|Cortisol||Increases blood sugar levels and suppresses the immune system||Adrenal cortex|
|Norepinephrine, epinephrine||Adrenal medulla|
|Insulin (β cells)||It helps absorb glucose from the blood to tissue and is also released from the liver.||Pancreas|
|Glucagon (α cells)||It helps absorb glucose into the liver to form glycogen||Pancreas|
|Parathyroid hormone (PTH||Parathyroid|
|Testosterone||It builds muscles, gives masculine character, and also stimulates the formation of sperms.||Testes|
|Estrogens||Development of the female reproductive system.||Ovaries & Placenta|
|Progesterone||Menstruation, Aids zygote implantation, Lactation & sexual drive||Ovaries & Placenta|
|Human chorionic gonadotropin (HCG)||Placenta|
|Renin||It helps maintain blood volume and thereby the blood pressure||Kidney|
|1,25-Dihydroxycholecalciferol||Rises blood calcium levels||kidney/nephron|
|Erythropoietin||Stimulates the formation of red blood cells.||Kidney|
|Atrial natriuretic peptide (ANP)||Balance of water, sodium, potassium, and fat in the body||Heart muscle|
|Gastrin||To secrete gastric juice||Stomach|
|Secretin||Water levels and water balance in the body||Small intestine/duodenum|
|Cholecystokinin (CCK)||Stimulates fat and protein digestion in the intestine.|
|Leptin||Regulates energy balance. Inhibits hunger if needed||adipose cells|
|Ghrelin||Stimulates hunger||Gastro intestine|
From the above list, the ones secreted by the hypothalamus, anterior, and posterior pituitary are formed in the brain.
While the remaining hormones are formed outside the brain, they are carried on by blood to different regions once released.
The hormones reaching the corresponding regions elicit their response.
It is quite impressive to note that the ones released from the brain also regulate the secretion of other hormones.
So it indicates that their secretion is controlled by the brain and indirectly all the other hormones too.
Thus the whole body physiology seems to be under the control of the brain.
Any emotional disturbance to the brain can lead to an alteration in the secretion of these hormones. Thus we can see that during emotional changes, we experience hormonal imbalance too.