Endocrine Control of Growth Flashcards Preview

Week 41: Normal/Abnormal Growth and Development > Endocrine Control of Growth > Flashcards

Flashcards in Endocrine Control of Growth Deck (17)
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1

Important factors during fetal growth

IGF-1 and IGF-2
Insulin
EGF and TGF-a
Little role for GH and no role of thyroid hormones

2

Some determinants of post-natal growth

Nutrition/general health status
Psychosocial environment
Genetic factors
Absence of primary bone abnormalities
Hormonal factors

3

Psychosocial dwarfism

Poor home environment and inadequate parenting
Abnormal GH secretion but GH treatment is not effective
Treatment: removal from environment and demonstration of catch-up growth

4

Direct GH actions

Lipolysis
Increased amino acids transport into tissues
Increases protein synthesis in liver

5

Sites of GH/IGF action

Epiphysis: stimulation of growth
Bone: stimulate osteoclast/blast activity, increase bone mass by endochondral bone formation
Adipose tissue: acute insulin-like effects followed by increased lipolysis
Muscle: increased AA transport, increased N retention, increased lean tissue

6

Effects on blood sugar
1. GH
2. IGFs

1. Hyperglycemia
2. Hypoglycemia

7

SRIF

Somatostatin
Hypothalamic peptide that inhibits pituitary release of GH

8

Factors that promote GH release

Sleep
Stress
Exercise
Hypoglycemia
Arginine
Alpha-adrenergic agonists
Beta-adrenergic antagonists
Estrogens

9

IGFBP-3

IGF Binding Protein
Coordinates GH and IGF1 actions
Regulates IGF1 delivery to the growth plate

10

PIT-1

Transcription factor
Pituitary specific TF that is responsible for pituitary development and hormone expression
Results in hypoplasia of GH, PRL, and TSH secreting cells
Hard to test for, have to diagnose clinically

11

GH Deficiency

Severe postnatal decrease in height velocity with tendency to truncal obesity
Hypoglycemia, micropenis, prolonged jaundice
High pitched voice, thin hair/skin
Delayed bone age and teeth eruption
Delayed puberty
Midline problems (cleft palate)

12

2 major hormonal factors in growth

GH
TH

13

Post natal hypothyroidism

Profound growth failure and virtual arrest of skeletal maturation
TH has a permissive effect on GH secretion so hypothyroidism will result in blunted GH response on provocative testing

14

Signs and symptoms of hypothyroidism

Short stature +/- delayed puberty
Obesity
Low growth velocity
Decreased energy, increased sleep
Dry skin, constipation, cold intolerance
Developmental delay

15

Signs of ACTH deficiency

Fatigue, weakness
GI complaints: vomiting, diarrhea, abdo pain
Circulatory collapse
Weight loss, growth retardation
Hypoglycemia

16

Do you replace ACTH or TH first?

ACTH
Avoid precipitating an adrenal crisis

17

What hormone causes the pubertal growth spurt?

Estrogens