Hormones, enzymes, and neural system
Vital to all physiological processes in the body is the functioning of hormones and enzymes. Both are considered the keys to vital living and the core of cell health. Keeping both in an optimal condition is the first task of healthy aging. But before moving into the optimization it is important to understand functioning and production. In enclosed tables, a short oversight of major functions is given.
List of Hormones and their Functions in the human body
|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 the adrenal gland to secrete gluco 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 adrenal cortex to produce||(AP)|
|Prolactin||Stimulates milk formation||(AP)|
|Follicle-stimulating hormone (FSH)||Stimulates to form sperms in male and Ova in the female.||(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 enhanced deposition in bone, decrease in intestinal absorption and expulsion by the kidney.||Thyroid|
|Cortisol||Increases blood sugar levels and suppress the immune system||Adrenal cortex|
|Aldosterone||regulate blood pressure, sodium conservation in the kidney||Adrenal cortex|
|Norepinephrine||Also called noradrenaline, mobilize the brain and body for action, promotes vasoconstriction, increase blood glucose levels and levels of circulating free fatty acids||Adrenal medulla, locus coeruleus (brain)|
|Epinephrine||Also known as Adrenaline, increase in heart rate, muscle strength, blood pressure, and sugar metabolism, causes smooth muscle relaxation in the airways but causes contraction of the smooth muscle that lines most arterioles||Adrenal medulla|
|Insulin (β cells)||Helps absorb glucose from the blood to tissue and also release from the liver||Pancreas|
|Glucagon (α cells)||Helps absorb glucose into the liver to form glycogen||Pancreas|
|Parathyroid hormone (PTH)||stimulates osteoclast activity within the bone marrow,||Parathyroid|
|Testosterone||Builds muscles, give masculine character and also stimulate the formation of sperms||Testes|
|Estrogens||Development of female reproductive system.||Ovaries & Placenta|
|Progesterone||Menstruation, Aids zygote implantation, Lactation & sexual drive||Ovaries & Placenta|
|Human chorionic gonadotropin (HCG)||Supporting the ovarian corpus luteum, which in turn supports the endometrial lining and therefore maintains pregnancy but also a cancer marker when increased levels measured in mature subjects||Placenta|
|Human somatomammotropin (HCS)||Regulates carbohydrate and protein metabolism of the mother to ensure delivery to the fetus of glucose for energy and protein for fetal growth||Placenta|
|Renin||Helps maintain blood volume and thereby blood pressure||Kidney|
|1,25-Dihydroxycholecalciferol||Rises Blood calcium levels||kidney/nephron|
|Erythropoietin||Stimulates formation of red blood cells.||Kidney|
|Atrial natriuretic peptide (ANP)||the 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|
Amino Acid-Derived Hormones
The amino acid-derived hormones are relatively small moleculees that are derived from the amino acids tyrosine and tryptophan. Its chemical name end in “-ine”. Examples include epinephrine and norepinephrine, thyroxine and melatonin.
Peptide hormones include molecules that are short polypeptide chains, such as antidiuretic hormone and oxytocin produced in the brain and released into the blood. This class also includes small proteins, like growth hormones and large glycoproteins such as follicle-stimulating hormone produced by the pituitary. Amino acid-derived and polypeptide hormones are water-soluble and insoluble in lipids. These hormones cannot pass through plasma membranes of cells; therefore, their receptors are found on the surface of the target cells. The structures of peptide hormones oxytocin, growth hormone and follicle-stimulating hormone are much larger than those derived from cholesterol or amino acids.
Lipid-Derived Hormones (or Lipid-soluble Hormones)
Most lipid hormones are derived from cholesterol and thus are structurally similar to it. The primary class of lipid hormones in humans is the steroid hormones. Chemically, these hormones are usually ketones or alcohols; their chemical names end in “-ol” for alcohols or “-one” for ketones. Examples of steroid hormones include estradiol and testosterone. Other steroid hormones include aldosterone and cortisol, which are released by the adrenal glands along with some other types of androgens. Steroid hormones are insoluble in water and transported by transport proteins in the blood.
Eicosanoids also called ‘local hormones’ as they act on cells close to their site of production. Eicosanoids have a short lifespan and break down fast. There are different types of eicosanoids. Three most known types are prostaglandins, thromboxanes, and leukotrienes. Most eicosanoids are produced from arachidonic acid. Arachidonic acid is a polyunsaturated fatty acid and a type of omega-6 fatty acid.
Both enzymes and hormones, have specific functions in the body and often interact with each other.
The Pancreas produces both enzymes and hormones which are both active on the same channel but at a different angle. Amylase breaks down carbohydrate-containing food into solvable nutrients. After entering the blood system Insulin assist to get the glucose (carbohydrates) into the cell. Here we see an important additional effect of enzyme/hormone.
Another sample is the Adrenal cortical steroids promoting adenosine triphosphatase within the energy system. In the study of the aging process it is important to know which action comes first; the hormone activity or the enzymatic reaction.
The answer to this is complicated as it depends on the chemical pathway. Most hormones only become active after an exchange with enzymes. These enzymes are needed to change the shape of pro-hormones and actual active hormones to other active products.
Hormones have specific interaction levels at target cells:
Permissiveness – one hormone cannot function without the assistance of another hormone. This teamwork is needed for a full functioning of the reaction
Synergism – more than one hormone produces the same effect on a target cell. This avoids problems when a specific hormone shows a malfunction/error
Antagonism – one or more hormones oppose the action of another hormone. This is needed to end specific reactions and bring back to a neutral state.