Sex Steroids Flashcards

1
Q

Outline the basic pathway of Sex steroid synthesis

A
  • Cholesterol-> Pregnenolone
  • Pregnenolone -> Progesterone-> Testosterone
  • Pregnenolone-> Androstenedione-> Estrone OR Testosterone
  • Estrone and Testosterone can both-> Estradiol
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2
Q

With Steroid hormone- nuclear receptor binding, why is there a lag before seeing cellular effect?

A

Lag is due to time taken for gene transcription to occur

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3
Q

Does oestrogen bind to a nuclear or membrane receptor?

A

Both

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4
Q

Name the 3 types of sex steroid hormones

A
  • Oestrogens
  • Progestagens
  • Androgens
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5
Q

List the major effects of Oestradiol and Progestrone

A

Oestradiol;

  • Stimulates endometrium and breast growth
  • Stimulates Progesterone production

Progesterone;

  • Stimulates endometrium and breast growth
  • Maintains pregnancy
  • Inhibits Oestradiol production
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6
Q

List the major effects of Testosterone

A

Stimulates male characteristics

hair, voice, aggression, anabolism

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7
Q

What 3 tissues can have hyperplasia or cancer due to Oestrogen side effects

List 3 other side effects of Oestrogen

A
  • Breast
  • Endometrial
  • Ovarian
  • Fluid retention
  • Increased coagulability-> Embolism
  • Impaired glucose tolerance
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8
Q

List 3 actions and some side effects of Progesterone

Not an exhaustive list

A

Actions;

  • Anabolic (just like Oestrogen)
  • Mood changes
  • Secretory endometrium

Side effects;

  • Weight gain, Acne
  • Fluid retention
  • Irritability, depression, PMS, lack of concentration
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9
Q

Why are men more at risk of atherosclerotic disease?

A

Due to metabolic effects of Testosterone, we get adverse effects on HDL/ LDL ratio

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10
Q

List 4 Pharmacokinetic features of Oestrogen drugs

A

Natural & Synthetic Oestreogens are well absorbed;

  • In GI tract, so can give ORALLY
  • From Skin & Mucous membranes, so can give TRANSDERMALLY
  • Metabolised in liver
  • Excreted in urine as Sulphates and Glucuronides
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11
Q

List 3 Pharmacokinetic features of Progesterone drugs

A
  • Bound to albumin, with some stored in adipose (so good for long acting preparations)
  • Metabolised in liver
  • Excreted in urine, conjugated to Glucuronic acid
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12
Q

COCP and POP are metabolised in the liver by what enzymes?

List 3 types of drugs/ substances that INDUCE these enzymes, leading to reduced contraceptive efficacy

A
  • CYP 450s
  1. Anti-epileptics (Carbamazepine or Phenytoin)
  2. Some antibiotics (Rifampicin or Rifabutin)
  3. Some natural products (St Johns Wort)
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13
Q

How do Soya protein products alter Oestrogen’s effects

A
  • Enhance oestrogen absorption and reduce its storage in adipose & muscle
  • Thus half-life reduced from 15 to 7 hours
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14
Q

Suggest 2 reasons for prescribing HRT

A
  • Reduce menopausal symptoms
  • Protect against osteoporosis

(Protecting against heart disease is NOT a valid reason, as it is not effective)

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15
Q

List 5 routes of administering HRT

A
  • Oral
  • Transdermal
  • Implant
  • Nasal
  • Transvaginal
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16
Q

List some risks of HRT

Risks associated with length of treatment, so risk drops when treatment stops

A
  • Unopposed oestrogen (ERT)= Increased risk of Endometrial and ovarian cancers
  • Opposed Oestrogen (HRT)= Increased risk of Breast cancer
  • Increased risk of Venous Thromboembolism
  • Increased risk of Stroke
17
Q

What are Bisphosphonates?

How do they work?

A
  • Drugs that reduce bone resorption used to treat and prevent osteoporosis
  • Control osteoclast activity (prevent them from binding to bone)
18
Q

List 3 pharmacokinetic features of HRT drugs?

A
  • Long half life
  • Poor gut absorption
  • Absorption affected by food, so take on empty stomach
19
Q

List some ADRs of Bisphosphonates

A
  • Upper GI effects (Oesophagitis, stay seated or standing for 30mins after taking)
  • Hypocalcaemia (Check Ca and Vit D levels before treatment)
20
Q

Which enzyme converts Testosterone to Dihydrotestosterone?

Name a drug that inhibits this enzyme

Suggest a condition that this drug can be used to treat

A
  1. 5-Alpha-Reductase
  2. Finasteride
  3. Enlarged prostate
21
Q

List some features of Mifepristone/ RU486

A
  • Progesterone + Glucocorticoid receptor antagonist
  • Anti progesterone
  • Sensitises myometrium to prostaglandin-induced contractions (progesterone prevents contractions)
  • Used to terminate pregnancy
22
Q

Name 3 SERMS (Selective Oestrogen Receptor Modulators)

A
  • Tamoxifen
  • Clomiphene
  • Raloxifene (Bone selective, does not increase risk of endometrial cancer)
23
Q

List 3 features of Clomiphene

A
  • Used to treat an ovulation
  • Competes with oestrogen for binding to Oestrogen Receptor
  • Increases production of Ant. Pit. hormones to induce ovulation
24
Q

Describe the Pharmacokineitcs of Tamoxifen

A
  • Is a Pro-drug itself, so has little affinity for the Oestrogen receptor
  • Metabolised in liver-> Active derivatives
  • Active derivatives compete with Oestrogen for binding to Oestrogen Receptor)
25
Q

Compare the action of Tamoxifen in the breast and endometrium

A
  • Endometrium: Acts as agonist

Breast;

  • Acts as antagonist
  • Causes cell cycle arrest
26
Q

What type of drug is Ulipristal Acetate?

Suggest 2 uses

A
  • A Selective Progesterone Receptor Modulator
  • Emergency contraception
  • Treatment of Uterine fibroids
27
Q

How does Ulipristal Acetate work as Emery you contraception

A

Thought to be due to delay/ inhibition of ovulation