hormone response element

Examples of hormone response element in the following topics:

• Direct Gene Activation and the Second-Messenger System

  • Hormones can alter cell activity by binding with a receptor.
  • Upon binding to a hormone the receptor and hormone translocate into the nucleus, and bind to specific sequences of DNA known as hormone response elements (HREs).
  • Most hormone receptors are G protein-coupled receptors.
  • Hormone binding to the NR triggers translocation to the nucleus, where the NR binds to a specific sequence of DNA known as a hormone response element (HRE).
  • Distinguish between the hormone mechanisms of direct gene activation and the second-messenger system

• Overview of Endocrine Glands

  • Two hormones—oxytocin and antidiuretic hormone (ADH)—are produced and released this way.
  • The anterior pituitary is involved in sending hormones that control all other hormones of the body.
  • Through hormonal secretions, they regulate many essential bodily functions including biochemical balances that influence athletic training and general stress response.
  • These are released into the small intestine to aid in reducing food particles to basic elements that can be absorbed by the intestine and used by the body.
  • These are responsible for releasing hormones in response to stress through the synthesis of corticosteroids such as cortisol, and catecholamines such as epinephrine (adrenaline) and norepinephrine.

• Aging and the Endocrine System

  • Three hormone axes are affected by aging: growth hormone/insulin-like growth factor I, cortisol/dehydroepiandrosterone, and testoterone/estradiol.
  • The endocrine system consists of glands and organs that produce and release hormones that affect the body in different ways and help control functions including tissue homeostasis, growth and development, reproduction, response to stress, and metabolism.
  • In addition to lower circulating amounts of IGF-I, the responsiveness of bone to this protein has been shown to decrease in animal models.
  • DHEA is released from the adrenal cortex in response to adrenocorticotrophic hormone (ACTH).
  • Once it binds to the ER, a series of activation steps are initiated, resulting in the binding of the estrogen-ER complex to the estrogen responsive element (ERE).

• Hormone Receptors

  • Hormones activate a cellular response in the target cell by binding to a specific receptor in the target cell.
  • A hormone receptor is a molecule that binds to a specific hormone.
  • The hormone activity within a target cell is dependent on the effective concentration of hormone-receptor complexes that are formed.
  • Many hormones are composed of polypeptides—such as thyroid-stimulating hormones, follicle-stimulating hormones, luteinizing hormones, and insulin.
  • Ligand binding to the TR causes a dissociation of co-repressor and recruitment of co-activator proteins, which in turn recruit additional proteins (such as RNA polymerase) that are responsible for the transcription of downstream DNA into RNA, and eventually into protein that results in a change in cell function.

• Target Cell Specificity

  • Hormones target a limited number of cells (based on the presence of a specific receptor) as they circulate in the bloodstream.
  • In endocrinology, target cells can refer to the cells where hormones have an effect.
  • Target cells are capable of responding to hormones because they display receptors to which the circulating hormone can bind.
  • Modulation of these factors can control target cell response.
  • For example, after receptor stimulation the signaling target cell often sends feedback to the hormone-secreting tissue to down-regulate hormone expression.

• Action of Thyroid Hormones

  • The primary function of the thyroid is to produce the hormones triiodothyronine (T3), thyroxine (T4), and calcitonin.
  • T4 is thought to be a pro-hormone to the more metabolically active T3.
  • Calcitonin is another hormone released by the thyroid gland that is responsible for modulating blood calcium levels in conjunction with parathyroid hormone, which is released from the parathyroid.
  • Only a very small fraction of the circulating hormone is free—T4 0.03% and T3 0.3%.
  • Only the free fraction has hormonal activity.

• Interactions of Hormones at Target Cells

  • Hormones that act to return body conditions to within acceptable limits from opposite extremes are called antagonistic hormones.
  • It can be used to describe situations in which the presence of one hormone, at a certain concentration, is required to allow a second hormone to fully affect the target cell.
  • Hormones that act to return body conditions to within acceptable limits from opposite extremes are called antagonistic hormones.
  • The two glands most responsible for homeostasis are the thyroid and the parathyroid.
  • In response, glucose concentration decreases in the blood, and insulin secretion discontinues through negative feedback from the declining levels of glucose.

• Hormones of the Digestive System

  • There are five main hormones that aid and regulate the digestive system in mammals.
  • There are five main hormones that aid in regulation of the digestive system in mammals.
  • This hormone responds to the acidity of the chyme.
  • This hormone is secreted in response to fat in chyme.
  • The last hormone is leptin which also helps to suppress appetite.

• Overview of the Pituitary Gland

  • The pituitary gland is connected to the hypothalamus and secretes nine hormones that regulate body homeostasis.
  • The pituitary gland secretes hormones that regulate homeostasis.
  • The anterior pituitary receives signaling molecules from the hypothalamus, and in response, synthesizes and secretes seven important hormones including thyroid-stimulating hormone and growth hormone.
  • The posterior pituitary does not produce any hormones of its own, rather, it stores and secretes two hormones made in the hypothalamus—oxytocin and anti-diuretic hormone.

• Pituitary Gland Disorders

  • Disorders of pituitary gland can affect hormones which regulate growth and activity of other glands in the body.
  • The hypothalamus secretes a number of hormones, often according to a circadian rhythm, into blood vessels that supply the anterior pituitary; most of these are stimulatory (thyrotropin-releasing hormone, corticotropin-releasing hormone, gonadotropin-releasing hormone and growth hormone-releasing hormone), apart from dopamine, which suppresses prolactin production.
  • In response to the releasing hormone rate, the anterior pituitary produces its hormones (TSH, ACTH, LH, FSH, GH) that stimulate effector hormone glands in the body, although prolactin acts directly on the breast gland.
  • 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.
  • Generally, the finding of a combination of a low pituitary hormone together with a low hormone from the effector gland is indicative of hypopituitarism.