Hypothalamic-Pituitary Relationships and Biofeedback Pt 1

Question 1

Anterior pituitary hormone families: ACTH Family

Answer 1

-Corticotrophs secrete adrenocorticotropic hormone (ACTH)

Question 2

Anterior pituitary hormone families: TSH, FSH, LH Family

Answer 2

• Each of these hormones are comprised of a shared alpha subunit and a differing beta subunit
• Thyrotrophs secrete thyroid stimulating hormone
• Gonadotrophs secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
• human chorionic gonadotropin (hCG) shares same alpha subunit

Question 3

Anterior pituitary hormone families: GH, Prolactin Family

Answer 3

• Somatotrophs secrete growth-hormone (GH)

- Lactotrophs/Mammotrophs secrete prolactin

Question 4

Acromegaly

Answer 4

• Excess growth of soft tissues, cartilage & bones in face, hands and feet due to excessive growth hormone –> can also decrease sensitivity of peripheral tissues to insulin resulting in increased blood glucose lvls and secondary compensatory hyperinsulinemia
• Excess growth hormone AFTER closure of bone epiphyses due to promotion of growth of deep organs and cartilaginous tissue

Question 5

Gigantism

Answer 5

-Caused by excessive growth hormone lvls BEFORE closure of bone epiphyses which cause insulin-like growth factor-1 (IGF-1) lvls to also increase and stimulate long-bone growth

Question 6

Actions of oxytocin

Answer 6

1. Milk ejection/milk letdown - suckling (or sight, sound or smell of an infant) stimulates an increase in oxytocin release which then stimulates the contraction of myoepithelial cells lining the milk ducts
2. Uterine contraction - oxytocin release is stimulated by dilation of the cervix or orgasm, which then stimulates uterine contractions and causes a positive feedback loop

Question 7

How do the levels of growth hormone secretion fluctuate throughout the day?

Answer 7

• Highest secretion during the first couple of hours of sleep
• Also peaks w/ exercise or stress

Question 8

What physiologic events cause the stimulation of growth hormone release?

Answer 8

• Fasting/hunger/starvation
• Hypoglycemia
• Hormones of puberty
• Exercise
• Sleep
• Stress

Question 9

Increased carbohydrate intake + increased protein intake –> effects on GH

Answer 9

• Growth promoting factors (fed state)
• Liver will produce IGF-1 in response to GH causing:
  a. Mitogenesis
  b. Lipolysis
  c. Differentiation

Question 10

Increased carbohydrate intake + inadequate protein intake –> effects on GH

Answer 10

• Unfavorable growth conditions –> GH is inhibited and liver will not produce IGF-1:
  a. Lipogenesis
  b. Carbohydrate storage
  c. Weight gain

Question 11

Inadequate carbohydrate intake + increased protein intake –> effects on GH

Answer 11

• Fasted state –> peripheral metabolism shifts to lipids as energy source:
  a. Lipolysis
  b. Ketogenic metabolism
  c. Diabetogenic –> GH raises blood glucose by decreasing peripheral glucose uptake and stimulating hepatic gluconeogenesis (insulin insensitivity)

Question 12

How does growth hormone increase blood insulin lvls?

Answer 12

-Decreases glucose uptake and utilization by target tissues and increases lipolysis in adipose tissue –> increasing blood insulin lvls and causing insulin resistance

Question 13

How does growth hormone promote protein synthesis and organ growth?

Answer 13

• Increases uptake of AA and stimulates synthesis of DNA, RNA and proteins
• Mediated by somatomedins (IGF-1)

Question 14

How does growth hormone promote linear growth?

Answer 14

• Stimulates synthesis of DNA, RNA and protein
• Mediate by somatomedins (IGF-1)
• Increase metabolism in cartilage-forming cells and chondrocytes proliferation