Endocrinology Flashcards
Insulin is activated by removing what part?
C peptide
What is the most common thyroid disease in a woman of child bearing age
Grave’s
What happens to insulin and glucagon after a protein rich meal?
increase insulin, increase glucagon
Glucagon induces
Gluconeogensis
-makes glucose from amino acids/lactate etc
Glycogenolysis
-makes glucose from glycogen
What is the most common circulating hormone in females out of:
Dihydrotestosterone
Testosterone
Androstenedione
Androstenedione
? Common precursor
Aldosterone causes Na reabsorption from which parts of the kidney?
Distal convoluted tubule
and
Collecting duct
Patient presents with hypotension and hyperkalaemia - diagnosis?
Addison’s
Low cortisol and low aldosterone
What hormone regulates appetite and is important in obesity?
obese and diabetic which decrease appetite
Leptin
A pregnant woman presents for diabetes screening. She is Asian with BMI 36, FBS 5. mmol/l, 2 hrs ppr 7.1 mmol/l. How do you interpret her OGTT?
Normal
5.6
7.8
Vasopressin increases water re-absorption at
Distal convoluted tubules
and
Collecting duct
A patient’s postoperative serum electrolytes showed hyponatraemia
(sometimes hyperkalaemia)
Addison’s
(low cortisol, low aldosterone
low BP, low Na, high K+)
What hormone causes sodium reabsorption
Aldosterone
What do glucocorticoids cause (1 action)
Gluconeogenesis
high prolactin
normal FSH and LH
low progesteron
high TSH
what is the cause
hypothyroidism
Increased TRH
causes increased TSH and PRL
What cells produce androgen in the female
Theca cells
Free T3 in non pregnant women
1%
Free level of T4 in non pregnant woman
0.1%
What is the level of FSH in ovarian failure
> 40
What do foetal adrenal glands secrete which cause lung, liver, thyroid and GIT maturity
Cortisol
2 months Postoperative patient with history of lung cancer presented with worsening polyurea and has depression. what is the most likely electrolyte imbalance occurs to patient?
Nyponatraemia
(??SIADH)
How many copies of amino acid sequences present in TRH (thyrotropin releasing hormone) precursor?
6
Which type of tumor increases growth hormone secretion and leads to acromegaly?
Pituitary Adenoma
glucocorticoids are released from which layer of adrenal cortex?
zona fasciculata
What kind of cells produce parathyroid hormone (PTH)?
Chief cells
Post-op patient with diabetes and asthma becomes unwell. Na 112. Dx?
Addison’s disease
What is the chemical structure of Renin?
Glycoprotein
What is the most potent and abundant oestrogen in postmenopausal women?
Estrone
Which hormone promotes cartilage mitosis in epiphyseal plate ?
Growth hormone
Graph of cycle
Hormone X has 2 peaks
Peak 1 (bigger) - day 12
Peak 2 (smaller) - Day 21
What is hormone X?
Estradiol
What is the acid/base balance of Conn’s Syndrome?
Metabolic alkalosis
Causes of secondary hyperlipidemia include all the following except:
- DM / hyperthyroidism / chronic renal failure / alcohol / nephrotic syndrome
hyperthyroidism
Woman presents with anxiety, tachycardia and weakness.
TSH decrease, Free T4 increase, prolactin 400. Dx?
Grave’s
What inhibits glucagon release?
Increased fatty acids
Most common cause of hyperprolactinemia?
Primary hypothyroidism
What is the most common cause of the female urethral caruncle?
Hypoestrogenism
The most common cause of delay in puberty in males is:
Constitutional
Luteinizing hormone (LH) is structurally related to what other glycoprotein hormones?
BHCG, FSH and TSH
Sheehan syndrome affects?
Anterior pituitary
What steroid hormone is made from DHEA in the zona reticularis
Androstenedione
What is the most common cause of cushing’s syndrome?
Iatrogenic Steroid Administration
The progesterone receptor is an example of which type of receptor ?
Nuclear (transcription factor) receptor
What hormone secreted by placenta leading to fetal diuresis ?
Vasopressinase
Which structure produces inhibin?
Granulosa cells
Inhibin suppresses FSH
Which hormone prevent regression of corpus luteum?
BHCG
In which part of the cell does glycolysis take place?
Cystosol
The rate of growth hormone secretion follows a circardian rhythm. When is the highest peak of growth hormone release?
Deep Sleep
A 32-year-old female presents with a two month history of breathlessness, tachycardia and menstrual irregularity. Her Investigations revealed: (SEPT 2015)
SerumhCG negative
Serum T4 178 mmol/l
Serum TSH0.05 mU/L
Prolactin400 mmol/l
What is the most likely diagnosis?
Grave’s
No of carbons in Estrogen?
18
Most common endocrine disorder in reproductive age group
PCOS
Prostaglandin is
autocrine / paracrine / endocrine
paracrine
What is the most common cause of secondary hyperparathyroidism?
Chronic Renal Failure
Amenorrhoea with raised TSH, FSH and LH - what is the cause?
Premature ovarian failure
Precursor of testosterone in theca cell
Androstenedione
What cells produce calcitonin?
C cells of thyroid gland
7/40 feeling tired
TSH 8.5
T4 14
T3 5.4
Hypothyroidism
The TSH is elevated + symptom of fatigue (means is not ‘sub clinical?)
Which hormone has a structure similar to Prolactin?
Growth Hormone
Which enzyme is present in granulosa cells but not in theca cells?
Aromatase
Where in the female body is androgen produced? Two sites.
Adrenal Zona reticularis
Ovarian Theca cells
Take cholesterol –> DHEA –> Androstenedione
What is the major estrogen found in menopause?
Estrone
Which test is used to check ovarian reserves in pre menopausal women?
Anti-mullerian hormone
Antidiuretic hormone (ADH) is synthesised in which part of the brain?
PRODUCED: Supraoptic > Paraventricular nuclei of the hypothalamus.
RELEASED: posterior pituitary
What is the chemical structure of GnRH
Decapeptide
What is the chemical structure of Renin?
Protein
Where is prolactin produced that is not under dopaminergic control?
Maternal decidua
From where in the nephron is the enzyme renin secreted ?
Juxtaglomerular apparatus
Which signalling molecule stimulates a chain of events leading to Aldosterone release?
Renin
Low BP –>
Renin/Angiotensin –>
Aldosterone release –>
Na+ and water reabsorption, K+ excretion
What is the most common cause of endogenous Cushing’s syndrome?
Pituitary adenoma
What is the action of PTH
Hypocalcaemia –> PTH release:
PTH increases calcium
PTH decreases phosphate
Renin pathway
Decreased renal perfusion –> renin release
Angiotensinogen
[renin]>
angiotensin 1
[ace]>
angiotensin 2 –>
aldosterone secretion
Aldosterone causes Na and H20 retention
What electrolyte stimulates aldosterone release
Hyperkalaemia
Raised K+
raises aldosterone
Most common cancer of Cushing syndrome
Adrenal adenoma
Ratio of T4:T3
13:1
What cell type produces human placental lactogen?
syncytiotrophoblast
What causes raised prolactin in PCOS?
Unopposed high oestrogen
What is the electrolyte imbalance in primary hyperaldosteronism
HTN
Hypernatraemia
Hypokalaemia
Active form of Vit-D is produced in which organ?
Kidney
The most biologically active form of vitamin D is
1, 25-Dihydroxycholecalciferol (calcitrol)
What enzyme converts testosterone to DHT
5 alpha reductase
What cells produce prolactin?
What proportion of the anterior pituitary do they take up?
Lactotrophs
20%
What electrolyte is used to transport Iodine into the thyroid?
Chloride
When do progesterone levels peak during pregnancy?
At term
What is the half life of LH
20 minutes
What % of T3 is free
1%
Epiphyseal plates are closed at puberty by the action of which hormone?
Estradiol
What inhibits prolactin?
Dopamine
Where is GnRH released from which area of the brain + which abdominal organ
(it stimulates FSH/LH)
Preoptic area of the hypothalamus +
Liver release GnRH
(Anterior pituitary releases FSH/LH)
What should be measured in pregnancy to assess thyroid function
FREE T3/T4
Because there is
-increased total T3/T4
-decreased free T3/T4 because of
increased binding
Which hormone decreases osteoclast activity and increases cartilage deposition at long bones in a term fetus
Calcitonin
When do progesterone levels peak in normal pregnancy?
At term
Which hormone leads to nutrient transfer from mother to foetus
Human placental lactogen
Which hormone is raised in the menopause
FSH
Miscarriage can occur due to the withdrawal of which hormone?
Progesterone
What is TRH
A polypeptide ?
What do delta cells in pancreas secrete?
Somatostatin
What acid/base imbalance is caused by conn’s syndrome?
Metabolic alkalosis
What oestrogen is secreted by the placenta
estriol
When do HPL levels peak?
Near term
What is the pattern seen in cushing’s DISEASE
Increased ACTH
Increased cortisol
Increased GH
What pattern is seen in hypothyroidism?
Elevated TSH
Decreased T3/T4
