Glossary of Terms

A

ACTH
Acronym for Adrenocorticotrophic Hormone. Produced in the pituitary gland, it stimulates the outer layer of the adrenal glands to produce cortisol and androgen hormones. Levels of ACTH increase in response to stress, emotion, injury, and infection.

Adenosine Triphosphate (ATP)
This is the primary fuel used by cells to generate the biochemical reactions essential for life.

Adrenal Gland
The organ that sits on top of each kidney and that makes a variety of hormones including the sex hormones (testosterone, estrogen, and progesterone), stress hormones (epinephrine and norepinephrine), and steroid hormones (DHEA), among others.

Adrenaline (Epinephrine)
A hormone that prepares the body for danger or stress.

Aerobic Capacity
The body’s ability to process oxygen. It is a combination of lung capacity, the size of the capillaries, the pumping action of the heart, and transfer of oxygen from red blood cells to target tissues.

Aerobic Exercise
Exercise with a low enough intensity to facilitate adequate oxygen transfer to the muscle cells so that no buildup of lactic acid is observed. This type of exercise is useful for reducing insulin levels and lowering blood glucose.

Aging
The general deterioration of the body with increasing age.

Amino Acids
Building blocks of protein molecules necessary for every bodily process. The body does not produce essential amino acids, which are necessary for growth and development, but must obtain them through the diet. Nonessential amino acids are those that the body synthesizes itself. Growth Hormone is a complex molecule composed of 191 amino acids.

Amygdala
The portion of the limbic system in the brain that processes emotions.
— See also Limbic System

Anabolism
The process by which bone, muscle, and other tissue build up. Any process that produces energy in which simple substances are converted into more complex matter.
— See also Catabolism, Metabolism

Androgens
A group of hormones that cause the development of male secondary sex characteristics, including facial hair, deep voice, and increase in muscle mass.

Anti-Aging
Strategies, programs, and supplements that reduce, prevent, and reverse the decline of physiological function.

Antibody
A protein produced in the body in response to contact with an antigen. An antibody neutralizes the antigen and creates an immunity to that antigen. An integral part of the immune system.
— See also Antigen

Antigen
Any substance recognized as “foreign” by the immune system. In certain disorders, such as rheumatoid arthritis, the immune system mistakenly targets healthy body cells as foreign.
— See also Antibody

Antioxidant
A chemical molecule that prevents oxygen from reacting with other compounds to create free radicals.

Apoptosis
A form of cell death in which a programmed sequence of events leads to the destruction of cells without releasing harmful substances into the surrounding area. Apoptosis plays an important role in health by eliminating aged cells, unnecessary cells, and unhealthy cells.

Atherosclerosis
A disease of the artery walls in which the inner layer thickens and thus impairs blood flow. It is responsible for more deaths in the United States than any other condition.

B

Biomarkers
The ten markers for age that are now considered reversible. These markers typically grow worse as people age:

1. Aerobic Capacity
2. Basal Metabolic Rate
3. Blood Pressure
4. Blood-Sugar Tolerance
5. Body Fat
6. Body Temperature Regulation
7. Bone Density
8. Cholesterol/HDL Ratio
9. Lean Body Mass
10. Strength

Blood Glucose
The primary source of energy for the brain. Elevated blood glucose levels cause diabetes and accelerate aging.

C

Calcitonin
A hormone that slows the rate at which bone is broken down, thus decreasing the amount of calcium that is dissolved in the blood.

Calorie Restriction
The reduction of calories that maintains adequate levels of protein and essential fats while also supplying adequate amounts of micronutrients (vitamins and minerals).

Catabolism
A chemical process of the body in which energy is released for use in work, energy storage, or heat production. The body breaks down complex substances into simple compounds.
— See also Anabolism, Metabolism

Cerebrovascular Disease
Any disease affecting an artery supplying blood to the brain.

Chromosome
A long-chained molecule containing genes and genetic information. Each chromosome is made up of a double strand of DNA.

Chronobiology
The study of internal body rhythms in order to map hormonal, nerve, and immune system cyclical functions. Chronobiologists hope to design hormone replacement and other strategies based on these cycles that will work more effectively and safely than prescription drugs and help extend life.

Circadian Rhythm
The cycle in the body that runs approximately twenty-four hours.

Collagen
A fibrous protein that forms a connective tissue supporting the skin, bone, tendons, and cartilage.

Cortisol
The hormone released from the adrenal glands in response to stress or low blood glucose. Its primary mode of action in times of stress is to shut down eicosanoid synthesis.

D

Dendrites
Short multiple branches of neurons linked by impulses that carry electrical signals toward the cell body.

DHEA
Acronym for Dehydroepiandrosterone. This powerful hormone is produced by the adrenal glands and plays a role in the regulation and production of other hormones including testosterone and estrogen. Its primary function is to inhibit the binding of cortisol. DHEA also appears to facilitate improved cholesterol profiles, loss of body fat, increased muscle gain, etc.
— See also Cortisol

Diabetes
A condition in which blood glucose is not well controlled. Type 1 diabetics make no insulin, whereas Type 2 diabetics are characterized by the overproduction of insulin and the inability of the target cells to respond to the insulin.

DNA
Acronym for DeoxyriboNucleic Acid. The genetic material of all living things found mainly in the chromosomes in the nucleus of a cell. Along the length of each strand of DNA lie the genes, which contain the genetic material that controls the inheritance of traits.

E

Eicosanoid
A hormone derived from a 20-carbon atom, polyunsaturated fat. Eicosanoids are made by every cell in the body. As autocrine hormones, they are constantly produced by the cell to sample the external environment.

Endocrine System
The system of glands and other structures that secrete hormones into the bloodstream, including the adrenals, ovaries, pancreas, pineal, pituitary, testicles, and thyroid. These hormones then travel through the bloodstream to target tissues.
— See also Hormonal Synergy

Essential Fatty Acids
These are fats the body cannot make and therefore must be part of the diet. Essential fatty acids are also the building blocks of eicosanoids. There are two groups, omega-3 and omega-6 fatty acids, and each gives rise to a different group of eicosanoids.
— See also Eicosanoid

Enzyme
An organic catalyst produced by living cells but capable of acting independently. Enzymes are complex proteins capable of inducing chemical changes in other substances without being changed themselves.

F

Free Radical
A molecule containing an odd number of electrons, making it highly reactive and, as a result, potentially dangerous to healthy cells.

G

Gene
The basic unit of heredity. Genes are made of DNA.

Glucagon
A hormone produced in the pancreas that raises the level of blood glucose.

Glucose
The most common simple sugar, also known as dextrose; the chief source of energy in humans.

Glucose Tolerance
The ability of muscle cells and the liver to remove glucose from the bloodstream. As you age, glucose tolerance decreases.

Glycogen
Stored form of sugar in the liver and muscles that is released as glucose when needed by cells for energy.

Growth Factors
Like hormones, growth factors influence the functions of the body. Almost all tissues manufacture growth factors.
— See also IGF-1 & IGF-2

Growth Hormone (GH or HGH)
A hormone secreted by the pituitary gland that is instrumental in regulating growth. It is released in periodic bursts during the day and night, especially during sleep, and is controlled by the hypothalamus. HGH promotes protein building in all cells, increases use of fatty acids for energy, and reduces use of carbohydrates. Growth effects depend on the presence of thyroid hormone, insulin, and carbohydrate.

Growth Hormone Releasing Hormone (GHRH)
The hormone released from the hypothalamus that causes the release of growth hormone from the pituitary gland.

H

Heavy Metal
A category of elements that includes highly toxic metals such as arsenic, cadmium, lead, and mercury.

High Density Lipoprotein
The good cholesterol that helps remove cholesterol from cells. If insulin levels go up, the HDL levels go down. The lower your HDL level, the more likely you are to suffer cardiovascular complications.
— See also Triglycerides

Hippocampus
The portion of the limbic system in the brain that integrates incoming nerve impulses to the hypothalamus, and is also the memory center for the brain.

Homeopathy
The “energy medicine.” A branch of medical science based on the theory that “like treats like.” In other words, a symptom that results from taking a substance in its raw form can be alleviated by taking the same substance in a highly diluted and properly succussed, or shaken, form. This is somewhat like the vaccine principle.

• For more information, visit the Homeopathy Home website.

Homeostasis
State of equilibrium of the internal environment of the body that is maintained by dynamic processes of feedback and regulation.

Hormonal Synergy
All hormones are interconnected. The decline in growth hormone, or any other good hormone, has a domino effect throughout the entire endocrine system. Conversely, enhancing growth hormone, or any other good hormone, can have a revitalizing effect on other good hormones.
— See also Endocrine System

Hormone
A chemical produced by the endocrine glands or tissue that, when secreted into body fluids, has a specific effect on other organs and processes. Hormones are often referred to as “chemical messengers,” and they influence such diverse activities as growth, sexual development, metabolism, and sleep cycles. Hormones also are instrumental in maintaining the proper internal chemical and fluid balance.

Hyperinsulinemia
The excess production of insulin. This is usually a consequence of insulin resistance in which the cells do not respond to insulin to reduce blood glucose levels.

Hypertension
Abnormally high blood pressure, which increases the risk of heart attack or brain hemorrhage.

Hypothalamus
A portion of the brain that activates, controls, and integrates part of the nervous system, the endocrine processes, and many bodily functions, such as temperature, sleep, and appetite.

I

IGF-1 and IGF-2
Acronym for Insulin-like Growth Factors 1 & 2. Two substances produced primarily in the liver in response to hormonal stimulation. IGF-1 works directly with growth hormone to promote growth and regulate metabolism, while IGF-2 works primarily to maintain the health and function of nerves. The role of these two growth factors continues to be the focus of intense research.
— See also Growth Factors

Immunity
The quality of being highly resistant to a disease or antigen after initial exposure and response by the immune system.

Insulin
The hormone that drives incoming nutrients into cells for storage. Excess insulin is the primary pillar of aging.

Insulin Resistance
A condition in which the cells no longer respond well to insulin. As a result, the body secretes more insulin into the bloodstream in an effort to reduce blood glucose levels.

Interferon
A group of proteins released by cells that have been infected with a virus. Interferon appears to inhibit viral growth.

Isoflavones
Plant estrogens that are chemically structured like estrogen and have similar effects but are weaker. Soybeans contain two primary isoflavones.

K

Krebs Cycle
The Krebs Cycle, also called the Citric Acid Cycle, is a metabolic process — a series of chemical reactions — that produces at least 90% of the energy used to power the body. This energy is in the form of ATP (adenosine triphosphate) and is produced by the mitochondria, small sub-units within the cells.

L

Lean Body Mass
The total body weight minus the fat mass. Lean Body Mass includes the weight of all organs, skin, bones, water, collagen, and muscles.
— See also Muscle Mass, Percentage Body Fat

Limbic System
The part of the brain that is concerned with more primitive impulses and maintaining biological homeostasis.
— See also Amygdala

Lipids
Fat chains made of fatty acids.

Luteinizing Hormone
Stimulates ovulation and prepares a woman’s body for pregnancy. In men, it triggers the testes to produce male sex hormones.

Lymphatics
A circulatory system of vessels distinct from the blood vessel circulatory system that reaches most body areas. This system contains lymph fluid and immune system cells. Lymphatics drain into lymph nodes and, eventually, the bloodstream.

M

Melatonin
The hormone made in the pineal gland that controls circadian rhythms. It is also a powerful antioxidant for hydroxyl free radicals.

Metabolism
The sum of all chemical processes that take place in the body to convert food to energy and other substances needed to sustain life. The first step is the constructive phase (anabolism) in which smaller molecules (amino acids) are converted to larger molecules (proteins). The second phase is the destructive phase (catabolism) in which larger molecules (like glycogen, sugar stored in the liver) are converted to smaller molecules (like glucose, blood sugar). Exercise, body temperature, hormone activity, and digestion all affect metabolism.
— See also Anabolism, Catabolism

Muscle Mass (or Skeletal Muscle Mass)
Skeletal Muscle Mass is one of the parts of Lean Body Mass. It is the only type of muscle that can actively grow and develop through proper exercise and nutrition. Muscle can contain up to 79% water.
— See also Lean Body Mass

N

NADH
Also known as Nicotinamide adenine dinucleotide. Creates ATP that powers the muscles, heart, brain, nerves and cell repair — everything that needs power. Important element of the Krebs Cycle.
— See also Krebs Cycle

Neurotransmitter
A chemical that changes or results in the sending of nerve signals. Serotonin, norepinephrine, acetycholine, and dopamine are among the many neurotransmitters that send and receive messages in the brain and body.

Nutrients
Proteins, carbohydrates, fats, vitamins, and minerals. These are provided by food and are necessary for growth and the maintenance of life.

P

Pancreas
The gland that lies behind the stomach and produces the hormone insulin as well as secretes a digestive fluid.

Percentage Body Fat
This describes the percentage of total body weight that is composed of fat. The higher the percentage of body fat, the greater the likelihood of chronic disease, such as heart disease, cancer, or diabetes.
— See also Lean Body Mass

pH
Potential Hydrogen. A 15-step scale measuring acidity or alkalinity.

Pineal Gland
The hormone gland located in the brain that secretes melatonin. The pineal gland eventually begins to shrink and calcify during the aging process, thereby significantly reducing the amount of circulating melatonin.

Pituitary Gland
The small gland joined to the hypothalamus at the base of the brain. It supplies many hormones that control growth, sexual development, and a host of other essential body functions.

Protein
Any of a large group of complex, organic nitrogen compounds. Each is made up of linked amino acids that have the elements carbon, hydrogen, nitrogen, and oxygen. Protein is the main building material for muscles, blood, skin, hair, nails, and organs. It is also needed to form hormones, enzymes, and antibodies.

Protein Metabolism
The ways in which protein in foods is used by the body for energy and to make other proteins. Food proteins are first broken down into amino acids, then absorbed into the bloodstream and used in body cells to form new proteins.

R

Receptor
A molecule that recognizes a unique hormone. Once that hormone is bound to the receptor, the information carried by the hormone can now exert its biological action.

Recombinant
A cell or organism that results from the rejoining of genes in the DNA molecule. The change can occur naturally or synthetically.

Recombinant DNA
A DNA molecule that has been broken into pieces that are then put back together in a new form. Parts of DNA material from another organism may also be placed into the molecule.

S

Serotonin
A naturally occurring neurotransmitter derived from the amino acid tryptophan.

Somatopause
Like female menopause, the fall in growth hormone (somatotrophin) is predictable, and the effects profound. For this reason, it has been given a similar name, “Somatopause.” Two differences between growth hormone decline and estrogen decline are rate and reversibility. Whereas estrogen drops like a stone, growth hormone descends slowly, taking other hormones, and your youthfulness, with it. And while the estrogen drop is unavoidable by natural means, growth hormone decline is now more a matter of choice than a fact of human destiny.

Somatropin
Recombinant (rDNA) human growth hormone.

Somatotropin / Somatotrophin
The scientific name for human growth hormone (hGH).

Sublingual
Administration of supplements or medicines intended to rapidly enter the bloodstream by being placed and held “under the tongue.”

T

Telomerase
An enzyme, part protein and part RNA, that extends the telomere.

Telomere
One of the ends of each of the four “arms” of a chromosome.

Telomere Therapy
Treatment of chromosomes to lengthen their telomeres in order to prevent further aging of the cells to which they belong, for the ultimate purpose of increasing the human life span. In the case of cancer cells, treatment of the cells in order to prevent telomerase function and destroy the cells.

Testosterone
The hormone that promotes the building of muscle mass in males and libido in both sexes.

Thymus Gland
A small endocrine gland located in the upper chest that regulates the development of certain immune system cells and makes hormones important in maintaining a strong, healthy immune system.

Thyroid Gland
An organ at the front of the neck responsible for producing thyroxine. The thyroid begins to shrink as we age, slowly decreasing the amount of thyroxine available to the body. Replacing growth hormone may help maintain the integrity of the thyroid.

Thyroxine (Thyroid Hormone)
A hormone affecting body temperature and the metabolism of protein, fat, and carbohydrates. Thyroxine also keeps up growth hormone release, skeletal maturation, and the heart function.

Toxin
Any substance with the potential to cause disease or damage to body tissues.

Triglycerides
The form of fat found in various lipoproteins in the bloodstream. High levels of triglycerides are usually indicative of high levels of insulin. The ratio of triglycerides/HDL is a powerful indicator of insulin levels and is strongly predictive of future cardiovascular events.
— See also High Density Lipoprotein

V

Vitamin
Any of a group of substances required by the body for healthy growth, development, and cell repair.