Phosphorous and homeostasis disorders

phosphorous vs phosphate

same

What is phosphate in

• rna, dna nadp \atp/ adp

• oxidative phosphorylation

• glucose -6- phosphate

• phospholipids

What can cause mineralisation

phosphate and calcium

and extracellular fluid..

high conc and dietary

Where phosphate fand calcium soft tissue mineralisation

5.6

Where is phophorous

WITH calcium for bone mineralisation as hydroxyaperte..

RElationship between phosphorous and calcium

MUST keep the balance at a fine level belwo 5.6 if you tied them together.

Can also have nutritional secondary parathyroidism + have control mechanism with calcitrol and PTH - must be kept together to prevent illness..

what is a phosphatonin

A molecule which is released in the presence of low phosphorus..

Will help metabolise phosphorous in order too decrease its concentration in the blood.

secreted by the bone in response to increasing PO4..

Phosphaturic = increases renal PO4 eccretion

What is the most importanat phosphatonin involved in decreasing the bloods phosphorous concentration and how does it work

• Fibroblast growth factor (23)

• Secreted by bone in response to increase PO4 levels…

• Will increase the transport of Po4 into the urine so it is excreted

• Also will inhibit the Alpha - 1 hydroxalase enzyme in the kidney so that the calcitriol levels are overall decreased..

• Also anti PTH, to try and lower overall calcium levels

THE GOAL = To have lowered CA - P ratio so that it is below 5.6 and soft tissue mineralisation is prevented..

high phosphate foods are…

low in calcium e.g meat and grain..

controlled by calcitriol and VIT. D ow h

how do you excrete excess phosphate

• salivary losses

• FGG- 23.. this is a phopatonin, secreted by bone by increase of PO4, theses reduces the phosphate and can be tested for and is detected on the increased.e. see can at risk of mbd.,..

Dietary phosphorous

• may graze phosphorous deficient pasture without grain and this can lead too problems with bone mineralisation

• pica often seen in mineral deficiencies..

What can happen if there is excess phosphorous

• associated wtih calcium deficiency…

• Ideally Ca:P ration…

• All - Meat diets have have high calciium

• need to supplement grain for a balanced bone diet + in bones and teeth..

What can animals show when there is mineral deficiencies

PICA —> eating food that isnt food..

Dietary phosphorus

What 5 things control the intake of PO4

1. Dietry Intake (how much is ingested)

2. How much is ABSORVED from the GI system — this is promoted by calcitrol…

3. PTH - phosphorous is reabsorbed from bone, and from GI (overall net decrease due too urinary excretion)

4. Renal tubular resorption

(increase by tubular filtered load + lowered by PTH…

5. Phosphatonins (FG-23) This will decrease levels..

In what 3 ways is phosphate excretion controlled

• PTH - breaks down calcium and phosphate - so promotes renal PO$ losses

• Salivary losses + recycling (Cattle..)

• FGF-23 = Phosphatonin

What is a good way to quickly assess whether an animal e.g. a cat may end up suffereing from renal disease/ hyperparathyroudism..

• Can measure FGF-23 levels..

• will rise before the ACTUAL phosphorous levels rise..

• may be a precursor to hyperparathyroidism

FG-23 summary

Where is deficiency of phosphorous often seen…

• When there are herbivours are grazing on low quality pasture + no grain supplements..

• 
  

Ca:P ideal ration

close too 1

summary of control factors for Po4

What are the 4 actions of PTH

bone fast

bone slow

absorption

excretion

What is the most common cause of hyperphosphataemia..

RENal disease — reduced GFR therefore reduced phophorous clearance so it builds up in the blood..

What are the 6 ways theat hyper phosphataemia may occour..

• renal disease

• calcitrol will increase this absorption - toxicitiy you r and goeing and acromegaly form the tubules

• increased bone turnover… Osteolysis - hyperadrenocorticism.., cell lysis + tumour cell lysis syndrome — increased phosphate

• hypoparathyroidism - less pth

What is the clinical presentation of hyperphosphataemia… if renal disease.

May have associated clinical signs with renal disease

pu/pd vomitting.. + wieght loss

What may happen + symptoms from HIGH phosphate

• will cuase low calcium due too their relationshop…

• SOFT tissue mineralisation… + secondary hyperparathyroidism…

• Osteopenia, osteomalacia + rubber jaw…

• ACUTE hypocalcaemia = tetany + spasms + seizures..

What is secondary renal hyperparathyroidusm

most common side afffect of hyperphosphorous..

What are affects of secondary renal hyperparathryoidim

What is the interactions between pth and fgf 23

• PTH response to ionised calcium

• FGf 23 has Ia as the primary stimulus

• FGF23 reduces calcitriol…

What is this?

Rubber jaw signs, teeth are wobbly. Low calcium high phosphate, trying too increase calcium, therefore the rubber jaw is decreasing..

HOw do you treat hyPERphphatemais..

• renal failure..

• po4 restricted diets

what is 2 nutritional hyperprarthyroidism

dietry imbalance

ober stimulated the thyroid gland BECUASE the high phosphorus has mopped up the free caclcium…

Therfore more pth to break down bones ot creat calcium

may see a LARGE face as swlling replaces the rbokem down bone

what is ruminant hyperphphatermia..

can fet urolithisases in the bladder n- mineraliseation of the bladder and the kidney stones..

removes blockeages with the catheter..

how does hyPOphophatemias occour

• kidney cannot absorb it

• low PO4 levels

• reduced overall absorptoin

• redistrubution into intracellular compartmenat

• milk fever + eclampsia..

What are the clincal consewuesns of clow phosphorous

less mineralisation

pain and long term bone derfprmation

weakenes and pain of muscles

What is the issues of low phosphurou

if downer cows give both as will hel p solve both.

COw diagnostic tests..

Phophate + albumin..