Endocrine System. Lecture 2 Parathyroid hormone, calcium homeostasis and suprarenal hormones. Asso . Professor Dr Than Kyaw 24 September 2012. PARATHYROID GLAND. How many parathyroid glands in animals? Located within or near thyroid gland
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Parathyroid hormone, calcium homeostasis and suprarenal hormones
Asso. Professor Dr Than Kyaw
24 September 2012
1. Normal Thyroid Gland2. Parathyroid Gland3. Parathyroid Gland4. Enlarged Thyroid Gland
Promotes production of
Metabolized to 2nd precursors
in the liver
Parathormone is more important in the regulation of Calcium and Phosphorus than calcitonin.
- severe hypocalcemia
- often severe neuromuscular dysfunction
- recumbent (cow) and involuntary muscular spasm (dog) referred to tetany or eclampsia
- It may be due to impaired responsiveness of PTH target tissues (receptor expression)
- impaired Vit D activation
- infusion of glucose and calcium (calcium borogluconate)
- the animal usually recover after the treatment
- bone decalcification
- bone deformities
Adrenal cortex (outer part)
Cross section of the adrenal gland showing the contrasting appearance of the cortex and medulla
Magnification of boxed-I area in A that shows the different cell types associated with the the three zones of the cortex
- increases blood glucose level by glycolysis of liver glycogen
Use of glucocorticoids
- treatment of bovine ketosis
- anti-inflammatory activity
- ophthalmic preparation, ear-drops, skin ointment
Renin - secreted by juxtaglomerula cells of the kidney
Circulating blood globulin, angiotensinogen to form AngiotensinI
Low blood pressure
- Systemic arteriolar vasoconstriction
- Increase systemic blood pressure
Promote Na reabsorption
And retention of water
Mechanism of corticotropin (ACTH) on adrenocorticalsteroidogenesis.
1. Stimulation of the uptake of low-density lipoproteins (LDL), which are further processed to free cholesterol
2. Stimulation of the hydrolysis of stored cholesterol esters to generate free cholesterol
3. Stimulation of the transport of cholesterol into mitochondria, where cleavage of the
cholesterol side chain occurs
Promotion of the binding of cholesterol to the enzyme.
AC, Adenylcyclase; ATP, adenosine triphosphate;
cAMP, cyclic adenosine monophosphate; R, recaptor.
- alpha receptors (stimulatory, but not intestinal mucosa)
- beta receptors (inhibitory, but not cardiac muscle)
- hyperglycemia, lypolysis,
- calorigenic effect – increased muscle activity
Common in canines, not found in other animals
Lack of appetite,
Tremors or shaking,
Low body temperature,
Low heart rate, and
Pain in the hind quarters
Sex hormone deficiency
Plus signs indicate stimulation; minus signs indicate inhibition.
CRH, Corticotropinreleasing hormone.