Thyroid hormone

Question 1

What are some hormones that regulate growth?

Answer 1

• GH,
• IGF-1 and IGF-2
• insulin
• TH
• glucocorticoids
• androgens
• estrogens

Question 2

name the 2 thyroid hormones…

and what do they act as?

Answer 2

• Thyroxine (tetraiodothyronine or T4)
• Triiodothyronine (T3)

act via nuclear receptors and regulate transcription of cell proteins

Question 3

what is responsible for actions of THs on their target tissues?

Answer 3

•Free or unbound hormone is responsible for actions of THs on their target tissues

Question 4

what do Thyroid-binding globulin (TBG), albumin and transthyretin (TTR) do?

Answer 4

• Act as a large buffer pool of THs in the circulation
• Helps pro-long the half-lives of both T4 and T3
• Large pool of T4 provides a reserve of prohormone available for synthesis of T3

Question 5

What efffect does the thyroid hormones (THs) have on the basal metabolic rate (BMR)?

Answer 5

THs increase the BMR by stimulating both catabolic and anabolic reactions in pathways affecting fats, CHOs and proteins

Question 6

State what happens in…

1. CHO metabolism
2. Protein metabolism
3. Lipid metabolism

Answer 6

1. CHO metabolism

​THs increase hepatic gluconeogenic activity by inducing the expression of several key gluconeogenic enzymes

1. Protein metabolism

Increased proteolysis (in muscle) releases AAs to be used for hepatic gluconeogenesisHyperthyroidism: muscle wasting and weakness

1. Lipid metabolism

​Increased degradation of stored triglycerides in adipose tissue provides glycerol for hepatic gluconeogenesis

Question 7

What is hypothyroidism and hyperthyroidism?

Answer 7