LEC 1 - Hypothalamic + Pituitary Hormones Flashcards by Raegan Chambers

What seven hormones are released from the anterior pit.?

ACTH

GH
TSH

PRL
FSH

MSH

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What hormones are secreted from the posterior pit.?

ADH

Oxytocin

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What is the structure that is responsible for stimulating the pituitary gland?

Hypothalamus

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What does the hypothalamus integrate the activities of?

Endocrine + Nervous

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What is the endocrine system regulated by?

Pituitary

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What is the nervous system regulated by when it comes to the hypothalmus?

Kidney

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What is the major difference between anterior and posterior pituitary stimulation?

Posterior is directly stimulated by the hypothalamus

Anterior is stimulated by hormones released by the hypothlamus

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What two nuclei are responsible for stimulating the posterior pituitary?

Supraoptic

– and –

Paraventricular

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What artery carries the hormones that stimulate the anterior pituitary?

Superior hypophyseal artery

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-physis: Pituitary gland

Hypophysis

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-physis: Anterior pituitary

Adenohypophysis

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-physis: Posterior pituitary

Neurohypophysis

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What is the adenohypophysis derived from?

Oral mucosa

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What is the neurohypophysis derived from?

Nerual ectoderm

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What are the two types of regulatory loops when it comes to regulation of hormones?

Long

and

Short

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What makes something a short regulatory loop?

Hormone secreted by the pituitary (or goal hormone) is what negative regulates the hypothalamus

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What makes something a long regulatory loop?

A downstream by product of the hormone released is what negatively regulates the hypothalamus

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Term: Peptide hormones (Types?)

Chains of AA

Glycoproteins

Short polypeptides/small proteins

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What are important glycoproteins?

TSH + LH + FSH

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What are important short polypeptides?

ADH

Oxytocin

Prolactin

Insulin

Glucagon

PTH

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What are the ways that the peptide hormones work to induce changes in cells?

effect cAMP levels

effect Ca2+ levels

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How are cAMP levels affected by peptide hormones?

Stimulate G protein

cAMP is stimulated/inhibited

Affect Kinase levels

Ion channels/Enzymes

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What hormones of importants effect cAMP levels?

ADH

FSH

TSH

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How do hormones effect the cell in a way that calicum levels change?

Activate G protein receptor

PLC > DAG > PKC

Open calcium channel

Calmodulin activated

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What hormone works by changing the calcium levels in the cell?

Oxytocin

What are the characteristics of hormones that work through surface receptors?

Fast acting Pathways are already present, just increasing or decreasing activity

Term: Lipid dermivatives (Types?)

Carbon rings and side chains Built from FA's or cholesterol Eicosanoids + Steroid

What are the important eicosanoids?

Prostaglandins

What are eicosanoids derivatives of?

Arachodonic acid

What are steroids derivatives of?

Cholesterol

What are the important steroid hormones?

Androgens Estrogens Progestins

How do lipid hormones activate changes in the cell?

Diffusion through the membrane Bind to cytoplasmic receptors Go to nucleus and cause transcription of new protein

What are the characteristics of steroid hormones?

Induce signals slowly, because creating new signaling pathways Since different cells have different concentrations of receptors some will take longer to react then others

Term: AA derivatives (Types?)

Small molecules structurally related to individual AA's Tyrosine + Tryptophan

What is thyroid hormone made form?

Tyrosine

What are the signs a dog has diabetes insipidus?

Diluted urine Normal glucose + creatine levels in urine Increased hematocrit PU/PD

What are the two froms of DI? Whats wrong in each case?

Central - No ADH Nephrogenic - Kidneys not responding to ADH

How does ADH regulate water excretion?

Induces aquaporin 2 in the collecting duct

What is the mechanism by which aquaporin is inserted into the collecting duct?

ADH stimulates G protien Increase cAMP PKA stimulated Vesciles taken to membrane \*\*Aquaporin-3 always expressed

What type of hormone is vasopressin?

Peptide

What are the types of vasopressin?

AVP LVP (pigs) DDAVP (drug form)

Characteristics of LVP

From pigs so shorter duration and smaller response in cats, dogs, and horses

Characteristics of DDAVP

Modified structure to increase response and duration L-ARG changed to D-ARG Extra tail of AA added

What is the purpose of desmopressin?

Endogenous vasopressing replacement

In what form is DDAVP given?

Nasal spray Not well tollerated in this method by animals So given in conjunctiva - varies between animal Dose to effect

When is the injectable form of DDAVP given?

when conjunctival isn't tolerated

Why can oral tablets be given for DDAVP?

Hydrolysis of peptide, doesnt work well

What is the peak effect time in dogs for DDAVP? What is the duration of action?

peak = 2 to 6 hours Duration = 10 to 27 hours

What is the major side effect of DDAVP?

Increase Factor VIII + vWF Cause a hypercoagulable state = thormbotic events

What causes acromegaly?

Increased endogenous GH secretion secondary to an active pituitary adenoma

What are the signs of acromegaly?

Systolic cardiac murmur Hepatomegaly/Renomegaly PU/PD Polyphagia w/ weight gain Diabetic but unresponsive to insulin

Why is there a diabetogenic effect of GH?

GH stimulates liver to break down glcogen into glucose Fuesl growth effects

How does GH have glucose sparing effect?

Stimulates adipose cells to break down stored fat Fueling growth effects

What are the two methods to inhibit GH secretion?

Decrease levels of GH-RH Increase levels of GH-IH

What is released by the liver that causes the growth effects that is stimulated by GH?

IGF-1

Why can't we increase IGF-1 levels to inhibit GH expression?

Would promote hypoglycemia

What is the drug used to treat acromegaly?

Octreotide

What is octreotide? Type and mechanism

Synthetic, 8aa Exogenously increases the amount of GH-IH results in decrease in amount of circulating GH

How so octreotide aborbed and processed?

SC admin Rapidly absorbed Need to adjust if patient has renal disease

What is the drug used to increase milk production in cattle?

Somatotropin

What are the other uses for somatotropin other than milk production?

Increase growth rate + improved meat quality in pigs Increased lean to fat ratio in beef cattle Pituitary dwarfism in dogs

What type of hormone is somatropin?

peptide

How does somatotropin effect metabolic function?

Increased fat utilization by organs Increased glycogen hydrolysis Increased glucose avalible for milk

What does somatropin do in regards to mammary glands? How?

GH \> Liver \> IGF -1 Increases blood flow (via increased CO) Increased nutrient extraction

What is the reason for variability in output with milk in cows treated with somatotropin?

Primiparous cows \< multiparous cows Ambient temps Feed

What is the reaons for a cow to have ketogensis?

Increase engergy demands for lactation not met by diet Increase utilization of NEFA + conversion to BHB Enter starvation state reduces production

How can GH reduce ketosis?

Direct effect of decreasign BCS through increased lipolysis/glucose-sparing Indirect through better feed management

How is somatotropin given?

every 14 days depot preparation

What is the withdrawl time for somatotropin?

0 day

What are the adverse effects of somatotropin?

Mastitis + Laminitis DM + Acromegaly in Dogs Increased rate of twinning