Hormonal growth (week 9)

Question 1

hormones that stimulate growth

Answer 1

thyroid hormone
insulin
testosterone
oestrogens
growth hormone
Calcitonin
parathyroid hormone
vitamin D

Question 2

growth stages regulation

Answer 2

parental - maternal factors, fetal insulin and IGF-1
Infancy - genetic factors, GH production, thyroid hormone, IGF-1
Adolesence - GH, insulin, IGF-1 and sex hormones

Question 3

where is growth hormone released

Answer 3

from the somatotrophs of the anterior pituitary in response to stimulation of these cells by growth hormone releasing hormone (GHRH)

Question 4

synthesis of growth hormone

Answer 4

GH manufactured as a preprohormone in the rough endoplasmic reticulum of the somatotrophs of the anterior pituitary

final hormones is loaded into secretory granules from the Golgi apparatus

Question 5

what causes an increase in GH secretion

Answer 5

Sleep
Ghrelin
Exercise
High protein meals
Hypoglycemia

Question 6

what are the roles of GH

Answer 6

reduces glucose up take
increased lipolysis
increased RNA and protein synthesis
increased gluconeogenesis
increased IGBP

Question 7

what does GHR receptor activation initiat

Answer 7

JAK/STAT signaling cascade

Question 8

what are GH target cells

Answer 8

Liver, muscle and adipose tissue.
These tissue express the GH receptor. One GH molecule binds to two receptors.

Question 9

anabolic hormone

Answer 9

increased amino
increased protein biosynthesis
decreased proteolysis

Question 10

lipolytic hormone

Answer 10

increased lipid degradation
increased plasma fatty acid

Question 11

carbohydrate metabolism

Answer 11

increased blood glucose
increased hepatic gluconeogenesis

Question 12

how does GH stimulate cell reproduction

Answer 12

increased rate of mitosis
hyperplasia: increase in the number of cells, proliferation rate
example: increase in bone length

Question 13

what are the three negative feedback

Answer 13

High levels of IGF-1 and GH
* Stimulates GHIH/Somatostatin
High levels of IGF-1
* Decreased secretion of GH
High levels of GH
* Inhibits GHRH

Question 14

insulin like growth factor

Answer 14

GH stimulates release of IGF-1 – an insulin-like hormone
* IGF-1 regulates cell proliferation, cell differentiation and cell metabolism
* IGF-1 is bound by insulin-like growth factor binding proteins(IGFBPs) and further associates with acid-labile subunits (ALS)when being transported in serum (all of which are produced in the liver in response to GH stimulation)
* Some cancers, like prostate cancer, can overexpress IGFBP and respond to IGFs

Question 15

GH abnormalities

Answer 15

Pituitary dwarfism
Gigantism
Acromegaly

Question 16

which mutated genes lead to dwarfism

Answer 16

GH1 gene, GHRH, pit-1

Question 17

In gigantism what else is affected other than their size

Answer 17

tumor affects secretion of other hormones.
they experience glucose intolerance, hyperinsulinemia, hypertrophy and are prone to more infections

Question 18

Acromegaly

Answer 18

• GH hypersecretion in adulthood
• Usually a result of pituitary tumor(often macroadenoma)
• Untreated there is a two-fold increased risk of death