Genetic testing – Genetic tests are tests on blood and other tissue to find genetic disorders. About 900 such tests are available.

Glands – A gland is an organ in an animal's or human's body that synthesizes a substance for release such as hormones, often into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland).

Glucagon – Glucagon is a hormone involved in carbohydrate metabolism. Produced by the pancreas, it is released when the glucose level in the blood is low (hypoglycemia), causing the liver to convert stored glycogen into glucose and release it into the bloodstream.

Gonads – A gonad is an organ that makes gametes (sperm and egg cells). The gonads in males are the testes and the gonads in females are the ovaries.

Gonadotropins – Gonadotropins are hormones that stimulate the growth and activity of the gonads, especially any of several pituitary hormones that stimulate the function of the ovaries and testes.

Gondadotropin releasing hormone (GnRH) – GnRH, also known as Luteinizing-hormone releasing hormone (LHRH), is a peptide hormone responsible for the release of gonadotropins from the anterior pituitary. GNRH is synthesized and released by the hypothalamus (an upper part of the brain).

Glycemia – Glycemia is the concentration of glucose in the blood.

Graves' Disease – Graves' disease is the most common form of hyperthyroidism. It occurs when your immune system mistakenly attacks your thyroid gland and causes it to overproduce the hormone thyroxine.

Growth Hormone – Growth hormone is secreted by the pituitary gland and stimulates growth of bone and essentially all tissues of the body by building protein and breaking down fat to provide energy.

Gynecomastia – Gynecomastia is the development of abnormally large mammary glands (breast tissue) in males resulting in breast enlargement.


Hirsutism – Hirsutism is excessive growth of thick dark hair in locations where hair growth in women usually is minimal or absent but typical in men, such as the face or chest.

Hormone – Made by endocrine glands, hormones are chemical messengers that travel in the bloodstream to tissues or organs. They affect many processes, including growth, metabolism, sexual function, reproduction, and mood.

Hormone therapy – Hormone therapy is the use of hormones in medical treatment. For example, doctors may use hormone therapy to boost estrogen levels in menopausal women. Other examples include thyroid hormone replacement for thyroid deficiency and insulin therapy for diabetes.

Hot flashes – Hot flashes refer to the sudden wave of mild or intense body heat caused by dilation of capillaries in the skin resulting from decreased levels of estrogen.

Hydrocortisone – Hydrocortisone also called cortisol, a hormone produced by the adrenal cortex upon stimulation by ACTH that mediates various metabolic processes (as gluconeogenesis), has anti-inflammatory and immunosuppressive properties, and whose levels in the blood may become elevated in response to physical or psychological stress.

Hypoglycemia – Hypoglycemia, also called low blood sugar, occurs when your blood glucose level drops too low to provide enough energy for your body's activities.