Glossary Index by Letter

GFR

Glomerular filtration rate. GFR is a calculation of how efficiently the kidneys are filtering wastes from the blood. A traditional GFR calculation requires an injection into the bloodstream of a substance that is later measured in a 24-hour urine collection. Recently,...

GH

Growth Hormone, secreted by the pituitary gland; the major hormone responsible for height growth Also plays a role in maintenance of bone density in adults, body composition in that it builds muscle and breaks down fat, regulates lipids, and may play a role in...

GHRH

Growth hormone releasing hormone. GHRH, or growth hormone releasing hormone is a hypothalamic peptide that regulates the synthesis and secretion of growth hormone in the anterior pituitary gland. The growth hormone (GH) stimulation test measures the level of growth...

GHRIH

Growth hormone release inhibiting hormone (same as SRIF) Somatostatin inhibits growth hormone release in response to GHRH

GHRP

Growth hormone releasing peptide. Growth hormone releasing peptide (GHRP-6) is a synthetic hexapeptide which specifically stimulates secretion of growth hormone.

Gland

An organ of the body that produces materials (hormones) released into the bloodstream, such as the pituitary or pineal gland. Hormones influence metabolism and other body functions. Endocrine glands include the Adrenals, Hypothalamus, Islets of Langerhans in the...

Glucagon Test

Glucagon is a hormone that is produced by cells in the pancreas the function of which is to raise blood sugar. An alternative to the insulin tolerance test; used to test for normal function of the hypothalamus and pituitary gland; glucagon increases blood sugar...

Glucocorticoids

Medications used to decrease swelling around tumors. Medication to duplicate the effects of cortisol. Often used to treat adrenal insufficiency.

Glucose

A type of sugar found in the blood; an important source of energy in the body. Aldohexose occurring as the D form and found as a free monosaccharide in fruits and other parts of plants and in the normal blood of all animals; the end product of carbohydrate metabolism...

GnRH

The Gonadotropin Releasing Hormone, secreted by the hypothalamus; GnRH stimulates the release of LH and FSH from the pituitary gland. Must be secreted in a coordinated fashion for LH and FSH to be secreted properly and then to stimulate gonads. Patietns with...

GnRH Pulsatile Therapy

A form of treatment which uses a portable, battery-driven pump to replace the missing GnRH by releasing it in pulses at regular intervals, typically every 90 minutes. This pulsatility mimics the normal pulses of the GnRH producing cells. Restores fertility in 75% of...

Gonadotrophin

A hormone which regulates the function of the gonads; the two main gonadotrophins are LH and FSH, both released from the pituitary gland. Secreted in a regulated fashion with minute-to-minute variations that are important for gland function.

Growth Factor

A substance made by the body that functions to regulate cell division and cell survival. Some growth factors are also produced in the laboratory and used in biological therapy. A naturally occurring protein chemical that stimulates cell division and proliferation. It...

GRS

Growth Hormone Research Society. The Growth Hormone Research Society (GRS) was founded in 1992 to provide a forum for the study and exchange of ideas on all aspects of growth hormone (GH) physiology, and diseases involving abnormalities of the GH axis.

Gynecomastia

A usually harmless female-like enlargement of one or both breasts in males; occurs commonly in teen-aged boys, but may be a characteristic of some hypogonadal males. Excessive development of the male mammary glands, even to the functional state; the development of...

HCG

Human Chorionic Gonadotrophin; a hormone which behaves like LH; made by the placenta, hCG may be extracted and used together with hMG to treat hypogonadism. This is what is measured in a pregnancy test.

HCG/HMG Therapy

Human Chorionic Gonadotropin / Human Menopausal Gonadotropin therapy. A type of treatment on offer to hypogonadal patients who wish to become fertile.

HDL

High-density lipoproteins. High density lipoproteins (HDL): the "good" cholesterol. HDL carry cholesterol in the blood from other parts of the body back to the liver, which leads to its removal from the body. So HDL help keep cholesterol from building up in the walls...

Hemianopsia

Loss of one half of the field of vision (the area that can be seen by each eye when staring straight ahead). Can occur in isolation or affecting both eyes. The most common form of vision loss due to pituitary tumors is loss of the outer half of vision in both eyes.