anterior pituitary

Question 1

what is Thyroid-stimulating Hormone (TSH) – thyrotropin

Answer 1

made by pituitary thyrotropes

acts on the thyroid gland to stimulate the release of thyroid hormones (T3 & T4)

Question 2

what is Luteinising Hormone (LH) & Follicle-stimulating Hormone (FSH) - gonadotropins

Answer 2

made by pituitary gonadotropes
act on the ovaries and testes to stimulate the production of sex hormones and also stimulate the production of eggs and sperm

Question 3

what is prolactin

Answer 3

made by pituitary mammotropes

acts on the breast to initiate and maintain milk production

Question 4

what is the synthesis of peptide hormones

Answer 4

Synthesized as large preprohormones (inactive)

Cleaved in the endoplasmic reticulum to prohormone (inactive)

Cleaved to the active hormone and packaged in Golgi

Release from vesicles via exocytosis (contains some prohormone)

Question 5

immunohistochemical staining for hormones

Answer 5

Anterior pituitary immunologically stained for:
1 .luteinizing hormone (black stain)
2. prolactin (purple stain)
3. unstained cells secrete the other pituitary hormones

Question 6

cell types in the anterior pituitary

Answer 6

somatropes, thyrotropes, corticotropes, gonadotropes and mammotropes

Question 7

what is a somatotrope

Answer 7

GH –> general tissue growth

Question 8

thyrotropes

Answer 8

TSH –> increase metabolic rate

Question 9

corticotropes

Answer 9

ACTH –> cortisol release

Question 10

gonadotropes

Answer 10

FSH/LH –> sec hormone release

Question 11

mammotropes

Answer 11

prolactin –> milk production

Question 12

Adenohypophysis

Answer 12

Releasing and inhibitory hormones released into blood in primary plexus.

Hormones remain concentrated (not diluted into general circulation).

Hormones delivered to anterior pituitary cells by secondary plexus.

Question 13

direct effects of growth hormone

Answer 13

reduced-fat stores, increased muscle bulk, increased organ size and function, and increased linear growth

Question 14

what is insulin-like growth factors

Answer 14

Produced by the liver (time lag of 12 hr)

Circulate bound to proteins (prolongs half-life)

Exerts the growth-promoting effects of growth hormone

GH and IGFs may work together
(eg. IGF stimulates proliferation of osteoclasts, GH stimulates differentiation of osteoclasts)

Question 15

what influences the hypothalamus

Answer 15

CNS, Metabolic, Endocrine

Question 16

how does the CNS impact the hypothalamus

Answer 16

REM sleep decreases GH release

Phase IV sleep increases GH release

Question 17

how does metabolism impact hypothalamus

Answer 17

Glucose inhibits GH release

Amino acids increase GH release

Question 18

how does the endocrine affect hypothalamus

Answer 18

Cortisol decreases GH release

Estrogen increases GH release

Question 19

dwarfism

Answer 19

lack of GH in child

Question 20

laron’s dwarf

Answer 20

lack of GH sensitivity

Question 21

gigantism

Answer 21

excess GH in children

Question 22

acromegaly

Answer 22

excess GH in adult

Question 23

what is acromegaly

Answer 23

Symptoms may be due to raised GH, or compression on tissues by a tumour, changes in the levels of other hormones.

Question 24

what are the symptoms of acromegaly

Answer 24

Arthralgia  (75%) 
  Paraesthesia or carpal tunnel syndrome  (40%) 
  Hypertension  (28%) 
  Excessive sweating (hyperhidrosis, 64%) 
  Sleep apnoea  (60%) 
  Visual field defects  (19%)
  Amenorrhea in women  (72%)
  Headaches  (55%)