Hormones are nonnutritive chemicals which act as intercellular messengers and are produced in trace

amounts. Hormones are chemical messengers that regulate various physiological functions in the body.
The endocrine system is a complex network of glands and organs that produce and secrete hormones.
Apart from the glands listed below there are some other organs, e.g., gastrointestinal tract, liver, kidney,
heart also produce hormones.

Endocrine Hormones Released Function in the Body

Gland
Hypothalamus Releasing hormones e.g. stimulate secretion of pituitary hormones
Gonadotrophin releasing
hormone
Inhibiting hormones e.g. inhibit secretions of pituitary hormones
somatostatin inhibits
release of GH from
pituitary
Pituitary Gland Growth Hormone (GH) Stimulates growth and cell reproduction
Over secretion – gigantism, Acromegaly
Low secretion – dwarfism
Thyroid Stimulating Regulates thyroid gland activity
Hormone (TSH)
Adrenocorticotropic Controls adrenal gland function
Hormone (ACTH)
Follicle-Stimulating Regulates reproductive processes
Hormone (FSH)
Luteinizing Hormone (LH) Regulates reproductive processes
Prolactin Stimulates growth of mammary glands and
milk production in females
Oxytocin Acts on smooth muscles and causes
contraction. Uterus contraction during
childbirth & milk ejection from mammary
glands.
Vasopressin or Anti- Acts on kidney and stimulates water and
Diuretic hormone (ADH) electrolyte retention in body.
Low ADH = water loss = Diabetes insipidus
Thyroid Gland Tetraiodothyronine or Regulates metabolism and energy production
Thyroxine (T4)
Triiodothyronine (T3) Regulates metabolism and energy production
Protein hormone called which regulates the blood calcium levels
thyrocalcitonin (TCT)
Note: Iodine needed for functioning of thyroid. Deficiency of Iodine = Goitre (swelling of
Thyroid) Grave’s disease is a form of hyperthyroidism
Parathyroid Peptide Hormone called Regulates calcium levels in the blood. Releases
Glands Parathyroid Hormone calcium from bones.
(PTH)
Adrenal Cortisol (glucocorticoid) Regulates metabolism and immune response.
Glands Increases Carbohydrate and fat metabolism.
Inhibit cellular uptake and utilization of amino
acids. Also produces anti-inflammatory
reactions and suppresses the immune response.
Also stimulates the RBC production.
Epinephrine (Adrenaline) Initiates "fight or flight" response. Sweating.
Rasing of hairs, alertness. Breakdown of
glycogen and increase in glucose in blood.
Noradrenaline - Same as above -
(norepinephrine)
Aldosterone Regulates blood pressure, osmotic balance and
electrolyte balance. Stimulates the reabsorption
of Na+ and water and excretion of K+ and
phosphate ions.
Pancreas Insulin (from β-cells of Reduces blood sugar (glucose) levels. Causes
Pancreas) absorption of glucose by Cells.
Glucagon (from α-cells of Increases blood sugar (glucose) levels. Breaks
Pancreas) Glycogen in liver into glucose.
Note: If insulin is not produced in sufficient quantity (Type 1) or cells do not respond to
insulin (Type 2) it leads to diabetes mellitus.
Pineal Gland Melatonin Regulates sleep-wake cycle and circadian
rhythms
Thymus Gland Thymosin Supports development of T-lymphocytes
(immune cells). Also promotes formation of
antibodies.
Ovaries (in Estrogen Regulates female reproductive system and
females) secondary sexual characteristics
Progesterone Supports pregnancy and menstrual cycle
regulation
Testes (in Testosterone Regulates male reproductive system and
males) secondary sexual characteristics