growth hormone

(noun)

any polypeptide hormone secreted by the pituitary gland that promotes growth and regulates the metabolism of carbohydrates, proteins, and lipids

Related Terms

Examples of growth hormone in the following topics:

  • Hormonal Regulation of Growth

    • Body growth is controlled by growth hormone (GH), produced by the anterior pituitary, and IGF-1, whose production is stimulated by GH.
    • Hormonal regulation is required for the growth and replication of most cells in the body.
    • GH release is stimulated by growth hormone-releasing hormone (GHRH) and is inhibited by growth hormone-inhibiting hormone (GHIH), also called somatostatin.
    • A balanced production of growth hormone is critical for proper development.
    • Oversecretion of growth hormone can lead to gigantism in children, causing excessive growth.

  • Hormonal Abnormalities and Height

    • Abnormal production of growth hormone due to tumors on the pituitary or other genetic causes can cause pathological changes in growth.
    • However, if these are not factors, then growth hormone deficiency may be the cause.
    • Growth hormone deficiency (GHD) is a medical condition in which the body produces insufficient growth hormone.
    • Growth hormone, also called somatotropin, is a polypeptide hormone which stimulates growth and cell reproduction.
    • Growth hormone deficiency has no single definite cause.

  • Growth Factors

    • Growth factors, cytokines and hormones are all chemical messengers that mediate intercellular communication.
    • Growth factors are typically cytokines or hormones, but not all cytokines and hormones are growth factors.
    • A cytokine differs from a hormone in that it is not secreted from a gland.
    • As with cytokines some are involved with growth, such as growth hormone produced by the anterior pituitary gland and may be classed as growth factors, but others are not.
    • The majority of growth factors shown above are cytokines such as GM-CSF, however the hormone EPO secreted by the kidney plays a key role in erythrocyte (red blood cell) proliferation.

  • Pituitary Gland Disorders

    • Disorders of pituitary gland can affect hormones which regulate growth and activity of other glands in the body.
    • Growth hormone (GH) excess is rare in children and is referred to as pituitary gigantism , because the excessive growth hormone produces excessive growth of bones and the child can achieve excessive height; from 2.1 to 2.7 m (6'11" to 8'11") in stature by adulthood if left untreated.
    • If elevated growth hormone levels occur before the closure of the epiphyses (i.e. in prepubertal children), then gigantism ensues.
    • Pituitary adenoma affects hormones which regulate growth and the activity of other glands in the body.
    • Measurement of ACTH and growth hormone usually requires dynamic testing, whereas the other hormones (LH/FSH, prolactin, TSH) can typically be tested with basal levels.

  • Lipid-Derived, Amino Acid-Derived, and Peptide Hormones

    • All hormones in the human body can be divided into lipid-derived, amino acid-derived, and peptide hormones.
    • The primary class of lipid hormones in humans is the steroid hormones.
    • Examples of steroid hormones include estradiol, which is an estrogen, or female sex hormone, and testosterone, which is an androgen, or male sex hormone.
    • This class also includes small proteins, such as growth hormones produced by the pituitary, and large glycoproteins, such as follicle-stimulating hormone produced by the pituitary .
    • The structures of peptide hormones (a) oxytocin, (b) growth hormone, and (c) follicle-stimulating hormone are shown.

  • The Anterior Pituitary

    • The anterior pituitary secretes seven hormones that regulate several physiological processes, including stress, growth, and reproduction.
    • The anterior pituitary regulates several physiological processes including stress, growth, reproduction, and lactation.
    • Follicle-stimulating hormone is a glycoprotein hormone that targets the gonads and effects the growth of the reproductive system.
    • Luteinizing hormone is a glycoprotein hormone that targets the gonads to effect sex hormone production.
    • Growth hormone is a polypeptide hormone that targets the liver and adipose tissue, which promotes growth through lipid and carbohydrate metabolism.

  • Hormone Functions

    • The endocrine system plays a role in growth, metabolism, and other processes by releasing hormones into the blood.
    • An animal's endocrine system controls body processes through the production, secretion, and regulation of hormones.
    • Target cells, those having a receptor for a signal, respond to a hormone when they express a specific receptor for that hormone.
    • Different tissue types may also respond differently to the same hormonal signal.
    • By releasing hormones, the endocrine system plays a role in growth, metabolism, and sexual development.

  • Hypothalamic-Pituitary Axis

    • The system releases hormones that act on target cells to regulate development, growth, energy metabolism, reproduction, and many behaviors.
    • The anterior pituitary produces seven hormones: growth hormone (GH), prolactin (PRL), thyroid-stimulating hormone (TSH), melanin-stimulating hormone (MSH), adrenocorticotropic hormone (ACTH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH).
    • Anterior pituitary hormones are sometimes referred to as tropic hormones because they control the functioning of other organs.
    • These regulatory hormones can be releasing hormones or inhibiting hormones, causing more or less of the anterior pituitary hormones to be secreted.
    • Negative feedback then regulates how much of these regulatory hormones are released and how much anterior pituitary hormone is secreted.

  • Control of Thyroid Hormone Release

    • TSH release in turn is stimulated by thyrotropin releasing hormone (TRH) from the hypothalamus.
    • Resulting in increased metabolism, growth, development and activation of numerous other systems controlled by thyroid hormones.
    • Thyroid hormones also provide negative feedback to the hypothalamus and anterior pituitary gland.
    • Thyroid hormones are produced from the thyroid under the influence of thyroid-stimulating hormone (TSH) from the anterior pituitary gland, which is itself under the control of thyroptropin-releasing hormone (TRH) secreted by the hypothalamus.
    • Thyroid hormones provide negative feedback, inhibiting secretion of TRH and TSH when blood levels are high.

  • Onset, Duration, and Half-Life of Hormone Activity

    • Hormone half-life and duration of activity are limited and vary from hormone to hormone.
    • Hormone half-life and duration of activity are limited and vary from hormone to hormone.
    • This image depicts the levels of certain hormones during the menstrual cycle (B), as they correspond to follicular growth and ovulation (A)1.
    • Follicle-Stimulating Hormone 2.
    • Luteinizing Hormone 4.