Endo And Repro

Question 1

Exogenous insulin
Effects?
Preps?
Side effects?

Answer 1

Same effects as endogenous insulin
Insulin preps. Concentrations of zinc and size of zinc crystals provide different durations of activity.
(Increasing activity time)
Crystalline zinc insulane—too frequent doses for routine use
Semilente
Isophane
Lente
Protamine zinc insulin
Glargine
Side effects? Hypoglycaemia - treat with IV glucose or glucagon

Question 2

Alternative diabetic agents

Answer 2

Sulphonureas - Glipizide
Stimulates insulin secretion, overdose milder than with insulin

Oral antihyperglycaemics–metformin
Does not stimulate insulin secretion , therefore no hypoglycaemia overdose.
Decrease glucose absorption for GI tract and glucose output from liver.
Increase insulin receptor sensitivity

Question 3

Treatment of insulinoma?

Answer 3

Too much insulin produced.
Can be treated dietary- frequent high protein and carbohydrate meals

Pharmacologically—Diazoxide
Activates k+ channel, inhibition of voltage gated ca2+ channels, inhibits insulin secretion

Question 4

Exogenous thyroid hormones- treating hypothyroidism 
Action
Absorption
Metabolism
Adverse effects.

Answer 4

T3 –Liothyronine (more active)
T4 – Levothyroxine

Action- same as endogenous thyroid hormones
Absorption- oral admin so absorbed from GI tract
Metabolism- 80% metabolised to T4 and then converted to T3 in peripheral tissues. T3 forms conjugated of glucoronide and sulphate in liver and excreted in bile.
Adverse effects? Hyperthyroidism

Question 5

Antithyroid agents
Action
Absorption
Metabolism 
Adverse effect?

Answer 5

Carbimazole—-metabolised to Methimazole
Action? Inhibits synthesis of T3 and T4
Absorption? Oral admin so absorbed by GI tract
Metabolism? In liver (other than cats)
Adverse effects? Can unmask renal failure. Hepatotoxicty- anorexia and vomiting

Question 6

Use of radioactive iodide

Answer 6

Destroys radioactive follicles, serum T3 and T4 normalise after. 1-2 weeks.
Can be expensive and may lead to hypothyroidism

Question 7

Glucocorticoids

Answer 7

Absorbed- GI tract, mucous membranes, skin
Distributed- plasma protein bound
Same actions as endogenous cortisol
Hydrocortisone (short acting) 
Prednisolone (intermediate acting)
Betamethasone (long acting)

Question 8

Adrenal steroid inhibitors

Answer 8

Treating hyperadrenocorticism

Mitotane–v. Lipophilic, long half life, cytotoxic to z.fasiculata and reticularis, not z. Glomerulsoa (won’t affect aldosterone)
Side effects? Hypoadrenocorticism, anorexia and vomiting.

Trilostane– competitive inhibitor
Also inhibits corticosteroids (aldosterone) and progesterone synthesis, don’t use in pregnant animals.
Side effects? Electrolyte abnormalities, lethargy, vomiting, anorexia

Question 9

Calcium replacement therapy

Answer 9

Calcium salts
Calcium carbonate/chloride/lactate

IV admin can cause cardiac arrhythmia
Oral admin- absorbed from SI
Long term therapy better achieved by increasing dietary calcium

Metabolised by VitD3

Question 10

Vit D3 analogues

Answer 10

Dihydrotachysterol (vitD2 analogue, needs converted)

Alfacalcidol - active VitD3 metabolite, does not require hydroxylation in kidney

Calcitriol- active form of VitD3

Different rate of onset and action
Oral admin, GI absorption, protein bound, excreted in faeces
Adverse effects? Hypercalcaemia, hyperphospataemia. Overdoses problem as long half life

Question 11

Erythropoietin analogues

Answer 11

Human recombinant erythropoietin
Increases number of committed stem cells in bone marrow that will develop int erythrocytes

Used as a substitute in cats and dogs with chronic renal disease
But can produce antibodies against it which will reduce efficacy

Question 12

Treatment of central diabetes insipidus

Answer 12

Diabetes insipidus - poor production of ADH but PostPit

Endogenous vasopressin (ADH)

Desmopressin better preferred
Vasopressin analogue
Intranasal and tablet form
Binds to stimulate ADH receptors in collecting duct
Longer acting and no vasoconstrictor activity

Question 13

Prolactin inhibitors

Answer 13

Cabergoline (galastop)
Potent inhibitor of pituitary lactotroph cells
Absorbed by GI, bound to albumin, metabolised by liver
Causes galactostasis and luteolysis (don’t use in pregnant animals)

Question 14

Oxytocin

Answer 14

Released from posterior pituitary
for milk let down and inducing myometrial contractions.
Only work if oxytocin receptors are present
Can accelerate parturition not induce it
Exogenous preparations are preferable to avoid contamination with ADH
Broken down in GI tract

Question 15

Durateston

Answer 15

Exogenous testosterone
Half life 8days
Same affects as endogenous testosterone

Question 16

Nandrolone

Answer 16

Weak androgen
Increases appetite and protein synthesis
Animals suffering from muscle weakness

Question 17

Danazol

Answer 17

Synthetic partial androgen receptor agonists
Treats immune mediated disease
Anabolic effects

Question 18

Finasteride

Answer 18

Androgen inhibitor

Inhibits testosterone metabolite

Question 19

Osaterone

Answer 19

Potent anti androgen
Competitor prevents binding of androgens
Chemically related to progesterone

Question 20

Oestriol

Answer 20

Synthetic short acting oestrogen
Treating urethral sphincter incompetence in spayed bitches
Don’t use in intact bitches due to oestrogenic effects

Question 21

Altrenogest

Answer 21

Oral synthetic progesterone

Used in horses and pigs

Question 22

Delmadinone (Tardak)

Answer 22

Synthetic progesterone
Inhibits FSH LH and testosterone
Chemically castrates

Question 23

Proligestone

Answer 23

Synthetic progesterone
Oestrous suppression in cats and dogs
Less side effects

Question 24

Aglepristone

Answer 24

Progesterone inhibitor
Can induce parturition
Cats and dogs only
Can cause abortion

Question 25

Synthetic GnRH

Answer 25

Surge of LH and FSH. Can induce ovulation
Gonadorelin
Buserelin
Destorelin (ovuplant) slow release implants

Question 26

Prostaglandins

Answer 26

Treating misalliance
Luteolysis
Produced and used locally
Readily absorbed through skin
PGF2a Dinoprost (lutalyse)
Synthetic PGF2a Colprostenol (estrumate)

Question 27

Synthetic gonadotrophs

Answer 27

hCG- human chorionic gonadotropin, mainly LH, induce ovulation, parenteral admin
eCG -equine chorionic gonadotropin, mainly FSH, oestrous induction and synchronisation
Combined- induction of oestrous in pigs and gilts
Folltropin V- induces superovulation in donor cows in embryo transfer

Question 28

Melatonin implants

Answer 28

ADH advances breeding season in sheep

Question 29

Clenbuterol

Answer 29

b2 agonist, smooth muscle relaxant, relaxes myometrium
Can delay parturition but not for long
Eg to fix a dystocia or relax uterus for c section

Question 30

Inducing parturition

Answer 30

Ewes and cows- cortisol to mimic foetal stress
Mares-oxytocin
Goats, sows, bitches, queens- prostaglandins to induce luteolysis