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4MT-2 Group 2:

Cala, Bianca Victoria

Calda, Danielle Alec

Cajucom, Mary Rozeline

Caritativo, Mico Raphael

De Guzman, Jose Eduardo

PARATHYROID & POSTERIOR PITUITARY HORMONES

POSTERIOR PITUITARY

The posterior pituitary (or neurohypophysis ) comprises the posterior lobe ofthe pituitary gland and is part of the endocrine system. It is largely a collectionof axonal projections from the hypothalamus that terminate behind the anterior pituitarygland. It is where neurohypophysial hormones are stored and released.

Hormones known classically as posterior pituitary hormones are synthesized by thehypothalamus; these include oxytocin and vasopressin. They are then stored in neurosecretoryvesicles (Herring Bodies) before being secreted by the posterior pituitary into the bloodstream.

Functions:

The posterior pituitary stores and secretes the following important endocrine hormones:Oxytocin, most of which is released from the paraventricular nucleus in the hypothalamus.Oxytocin is one of the few hormones to create a positive feedback l oop. For example, uterinecontractions stimulate the release of oxytocin from the posterior pituitary, which, in turn,increases uterine contractions. This positive feedback loop continues throughout labor.Antidiuretic hormone (ADH, also known a s vasopressin and AVP, arginine vasopressin), themajority of which is released from the supraoptic nucleus in the hypothalamus. Insufficientsecretion of vasopressin underlie s diabetesi nsipidus, a condition in which the body loses thecapacity to concentrate urine. Affected individuals excrete as much as 20 liters of dilute urineper day. Oversecretion of vasopressin causes the syndrome of inappropriate antidiuretichormone (SIADH).

https://en.wikipedia.org/wiki/Posterior_(anatomy)https://en.wikipedia.org/wiki/Pituitary_glandhttps://en.wikipedia.org/wiki/Endocrine_systemhttps://en.wikipedia.org/wiki/Axonhttps://en.wikipedia.org/wiki/Hypothalamushttps://en.wikipedia.org/wiki/Anterior_pituitary_glandhttps://en.wikipedia.org/wiki/Anterior_pituitary_glandhttps://en.wikipedia.org/wiki/Neurohypophysial_hormonehttps://www.boundless.com/physiology/definition/oxytocinhttps://www.boundless.com/physiology/definition/positive-feedbackhttps://www.boundless.com/physiology/definition/vasopressinhttps://www.boundless.com/physiology/definition/diabeteshttps://www.boundless.com/physiology/definition/diabeteshttps://www.boundless.com/physiology/definition/vasopressinhttps://www.boundless.com/physiology/definition/positive-feedbackhttps://www.boundless.com/physiology/definition/oxytocinhttps://en.wikipedia.org/wiki/Neurohypophysial_hormonehttps://en.wikipedia.org/wiki/Anterior_pituitary_glandhttps://en.wikipedia.org/wiki/Anterior_pituitary_glandhttps://en.wikipedia.org/wiki/Hypothalamushttps://en.wikipedia.org/wiki/Axonhttps://en.wikipedia.org/wiki/Endocrine_systemhttps://en.wikipedia.org/wiki/Pituitary_glandhttps://en.wikipedia.org/wiki/Posterior_(anatomy)

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1. ANTIDIURETIC HORMONE (ADH) / VASOPRESSIN

Effects on the Kidney

The single most important effect of antidiuretic hormone is to conserve body water by reducingthe loss of water in urine. A diuretic is an agent that increases the rate of urine formation. Injection

of small amounts of antidiuretic hormone into a person or animal results in antidiuresis ordecreased formation of urine, and the hormone was named for this effect.

Antidiuretic hormone binds to receptors on cells in the collecting ducts of the kidney andpromotes reabsorption of water back into the circulation. In the absense of antidiuretic hormone,the collecting ducts are virtually impermiable to water, and it flows out as urine.

Antidiuretic hormone stimulates water reabsorbtion by stimulating insertion of "waterchannels" or aquaporins into the membranes of kidney tubules. These channels transport solute-free water through tubular cells and back into blood, leading to a decrease in plasma osmolarity

and an increase osmolarity of urine.

Effects on the Vascular System

In many species, high concentrations of antidiuretic hormone cause widespread constriction ofarterioles, which leads to increased arterial pressure. It was for this effect that the namevasopressin was coined. In healthy humans, antidiuretic hormone has minimal pressor effects.

Regulation

The most important variable regulating antidiuretic hormone secretion is plasma osmolarity, or theconcentration of solutes in blood. Osmolarity is sensed in the hypothalamus by neurons known asan osmoreceptors , and those neurons, in turn, stimulate secretion from the neurons that produceantidiuretic hormone.

When plasma osmolarity is below a certain threshold, the osmoreceptors are not activated andsecretio of antidiuretic hormone is suppressed. When osmolarity increases above the threshold, theever-alert osmoreceptors recognize this as their cue to stimulate the neurons that secrete

antidiuretic hormone.

http://www.vivo.colostate.edu/hbooks/molecules/aquaporins.htmlhttp://www.vivo.colostate.edu/hbooks/molecules/aquaporins.html

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Clinical Significance

The most common disease of man and animals related to antidiuretic hormone is diabetesinsipidus . This condition can arise from either of two situations:

Hypothalamic ("central") diabetes insipidus results from a deficiency in secretion of

antidiuretic hormone from the posterior pituitary. Causes of this disease include headtrauma, and infections or tumors involving the hypothalamus.

Nephrogenic diabetes insipidus occurs when the kidney is unable to respond to antidiuretichormone. Most commonly, this results from some type of renal disease, but mutations inthe ADH receptor gene or in the gene encoding aquaporin-2 have also been demonstratedin affected humans.

The major sign of either type of diabetes insipidus is excessive urine production. Some humanpatients produce as much as 16 liters of urine per day! If adequate water is available forconsumption, the disease is rarely life-threatening, but withholding water can be very dangerous.

Hypothalamic diabetes insipidus can be treated with exogenous antidiuretic hormone.

ADH Measurement Test

ADH is a test that measures the amount of antidiuretic hormone (ADH) in blood

Indications:

Diagnosis and characterization of diabetes insipidus (DI)

Buildup of fluids in your body that are causing swelling or puffiness

Excessive amounts of urine

Thirst that is intense or uncontrollable

Procedure:

The patient should fast for at least 6 hours. No liquid intake is allowed.

A blood sample is needed.

The blood is acidified, then centrifuged.

After adding a buffer, the specimen is measured for ADH by RIA

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Normal Value:

Adults:

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painful contractions during the first few weeks of lactation. This also serves to assist the uterus in

clotting the placental attachment point postpartum. However, in knockout mice lacking the oxytocin

receptor, reproductive behavior and parturition are normal.

OXYTOCIN CHALLENGE TEST/ OXYTOCIN STRESS TEST

Used to determine how well the baby would undergo against the stress of labor

The mother is injected with Oxytocin, intravenously . Oxytocin would give the mother contractions 3-4 mins . apart for 1 whole hour. Heart rate of the baby is measured during these contractions

> (+) Increased Fetal Heart Rate

-Baby will not be able to tolerate contractions

-Wean Birth is recommended

>(-) Normal Fetal Heart Rate

-Baby will be able to tolerate contractions

-Normal Birth

*Lying flat on your back during the test will cause:

> Decrease blood pressure

>Decrease oxygen

>FALSE fetal distress on the monitor

PARATHYROID GLANDThe parathyroid glands are small endocrine glands in the neck that produce parathyroid

hormone. Humans usually have four parathyroid glands, which are usually located on the rearsurface of the thyroid gland, or, in rare cases, within the thyroid gland itself or in the chest.Parathyroid glands control the amount of calcium in the blood and within the bones.

https://en.wikipedia.org/wiki/Knockout_mousehttps://en.wikipedia.org/wiki/Parturitionhttp://en.wikipedia.org/wiki/Endocrine_systemhttp://en.wikipedia.org/wiki/Glandhttp://en.wikipedia.org/wiki/Parathyroid_hormonehttp://en.wikipedia.org/wiki/Parathyroid_hormonehttp://en.wikipedia.org/wiki/Thyroid_glandhttp://en.wikipedia.org/wiki/Thyroid_glandhttp://en.wikipedia.org/wiki/Parathyroid_hormonehttp://en.wikipedia.org/wiki/Parathyroid_hormonehttp://en.wikipedia.org/wiki/Glandhttp://en.wikipedia.org/wiki/Endocrine_systemhttps://en.wikipedia.org/wiki/Parturitionhttps://en.wikipedia.org/wiki/Knockout_mouse

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PARATHYROID HORMONE (PTH)

Parathyroid hormone (PTH, also known as parathormone) is a small protein that issecreted by

the chief cells of the parathyroid gland. It takes part in the control of calcium

and phosphate homeostasis, as well as bone physiology. Parathyroid hormone has effects antagonistic

to those of calcitonin.

Calcium

PTH increases blood calcium levels by stimulating osteoclasts to break down bone and release calcium.PTH also increases gastrointestinal calcium absorption by activating vitamin D, and promotes calcium

conservation (reabsorption) by the kidneys.

Phosphate

PTH is the major regulator of serum phosphate concentrations via actions on the kidney. It is an inhibitor

of proximal and also distal tubular reabsorption of phosphorus.

Through activation of Vitamin D the absorption of Phosphate is increased.

Regulation

Simulators

Decreased serum [Ca 2+]. Mild decreases in serum [Mg 2+]. An increase in serum phosphate (increased phosphate causes it to complex with serum calcium,

forming calcium phosphate, which reduces stimulation of Ca-sensitive receptors (CaSr) that do not sense calcium phosphate, triggering an increase in PTH)

Inhibitors

Increased serum [Ca 2+]. Severe decreases in serum [Mg 2+], which also produces symptoms of hypoparathyroidism (such

as hypocalcemia) .[11]

http://en.wikipedia.org/wiki/Parathyroid_hormonehttp://en.wikipedia.org/wiki/Proteinhttp://en.wikipedia.org/wiki/Phosphorushttp://en.wikipedia.org/wiki/Homeostasishttp://en.wikipedia.org/wiki/Calcitoninhttp://en.wikipedia.org/wiki/Osteoclasthttp://en.wikipedia.org/wiki/Vitamin_Dhttp://en.wikipedia.org/wiki/Kidneyhttp://en.wikipedia.org/wiki/Hypoparathyroidismhttp://en.wikipedia.org/wiki/Hypocalcemiahttp://en.wikipedia.org/wiki/Parathyroid_hormone#cite_note-brs-12http://en.wikipedia.org/wiki/Parathyroid_hormone#cite_note-brs-12http://en.wikipedia.org/wiki/Parathyroid_hormone#cite_note-brs-12http://en.wikipedia.org/wiki/Parathyroid_hormone#cite_note-brs-12http://en.wikipedia.org/wiki/Hypocalcemiahttp://en.wikipedia.org/wiki/Hypoparathyroidismhttp://en.wikipedia.org/wiki/Kidneyhttp://en.wikipedia.org/wiki/Vitamin_Dhttp://en.wikipedia.org/wiki/Osteoclasthttp://en.wikipedia.org/wiki/Calcitoninhttp://en.wikipedia.org/wiki/Homeostasishttp://en.wikipedia.org/wiki/Phosphorushttp://en.wikipedia.org/wiki/Proteinhttp://en.wikipedia.org/wiki/Parathyroid_hormone

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PARATHRYOID HORMONE TEST (PTHT)

An intact PTH is the most frequently ordered parathyroid hormone test. It is ordered to helpdiagnose the reason for a low or high calcium level and to help distinguish between parathyroid-relatedand non-parathyroid-related causes. It may also be ordered to monitor the effectiveness of treatmentwhen a patient has a parathyroid-related condition. A calcium test is almost always ordered along with a

PTH test. It is not just the levels in the blood that are important, but the balance between them and theresponse of the parathyroid glands to changing levels of calcium. Usually doctors are concerned abouteither severe imbalances in calcium regulation that may require medical intervention or in persistentimbalances that indicate an underlying problem.

It is also used to monitor patients with:

1.) Chronic Calcium Imbalances

2.) Surgery or Treatment of patients with Parathyroid Tumors

3.) Chronic Kidney Disease

4.) Hyperparathyroidism (Intraoperative PTHT)

Indications:

1.) Test for Calcium is abnormal

2.) Hypercalcemia

-Fatigue

-Nausea

-Muscle Pain

-Thirst

3.) Hypocalcemia

-Abdominal Pain

-Muscle Pain

-Tingling Fingers

http://labtestsonline.org/understanding/analytes/calciumhttp://labtestsonline.org/understanding/analytes/calcium

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Normal Value of PTH: 65 pg/mL

Normal Value of serum calcium: 2.25-2.5 mmol/l

Sources:

http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/hypopit/adh.html

http://www.mc.vanderbilt.edu/dept/obgyn/LD_Policies/OCT_CST_Policy.pdf

http://www.ncbi.nlm.nih.gov/pubmed/2673765

http://labtestsonline.org/understanding/analytes/adh/tab/test

http://www.nlm.nih.gov/medlineplus/ency/article/003702.htm

http://labtestsonline.org/understanding/analytes/pth/tab/test

http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/hypopit/adh.htmlhttp://labtestsonline.org/understanding/analytes/pth/tab/testhttp://labtestsonline.org/understanding/analytes/pth/tab/testhttp://labtestsonline.org/understanding/analytes/pth/tab/testhttp://www.vivo.colostate.edu/hbooks/pathphys/endocrine/hypopit/adh.html