3.1.1 Growth Hormone and Prolactin Physiology Flashcards

1
Q

What are some conditions that increase the amount of GHRH, which upreagulates somatotrophs?

A

GalphaS (adenylate cyclase and cAMP)

Ca++

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2
Q

What is used to sequester IGF1? In what form does IGF interact with target tissues?

A

IGFBP; unbound

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3
Q

What are some mutations that can alter the axis of GH?

A
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4
Q

What are some other mutations within the GH axis that can lead to growth abnormalities?

A
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5
Q

Describe the positive and negative feedback loops mediated by IGF-1 throughout the GH cascade.

A
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6
Q

What role do estrogens/androgens play in the regulation of growth?

A

Positive via the induction of GH and IGF-1

Negative via epiphyseal plate closure

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7
Q

Describe the regulation of prolactin and its unique characteristic within the anterior pituitary.

A

Prolactin is upregulated by PRH and downregulated by dopamine. It is unique in that it is under dominant negative regulation.

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8
Q

Prl secretion can lead to what condition?

A

Amenorrhea

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9
Q

What are three possible treatment mechanisms for GH excess?

A

Dopamine agonists

Somatostatin analogs

GH antagonists

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10
Q

What stimulates milk production? propels milk?

A

Production: Prl

Propels milk: Oxytocin

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11
Q

What role do glucocorticoids play in the regulation of growth?

A

Necessary for growth

Regulates the synthesis of GH and GHRH-R

Excess can lead to growth inhibition (directly at the level of cartilage and bone synthesis) and a catabolic state

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12
Q

What pathway acts downstream of the GH receptor which ultimately leads to activation of transcription factors?

A

Jak/Stat pathway

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13
Q

Describe the mechanism of how the hypothalmus can stimulate the somatotroph leading to increased IGF-1

A
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14
Q

What are some of the diabetogenic effects of GH?

A
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15
Q

Name the three sites of action of GH and its effects on those sites.

Name the three sites of action of IGF1 and its effects on those sites.

A
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16
Q

IGF1 can interact with this molecule’s receptor. As can this molecule interact with the receptor for IGF1. What molecule is this?

A

Insulin

17
Q

What protein has the same number of AAs and only varies in 29 AA locations?

A

Chorionic Somatomammotropin 1 and 2

18
Q

How do you feel about all of the endocrine cascades and feedback loops? Let’s check in on Holla

A

You aren’t alone….

19
Q

Compare GH and IGF-1: their structure, half-life, and activation pathway.

A
20
Q

Through what type of cells does prolactin upregulate dopamine?

A

Tuberoinfundibular Dopaminergic Neurons (TIDA)

21
Q

Describe the differentiation steps that lead to the 5 different cell types present in the anterior pituitary. What is the POU1F1 and GATA status of each cell type?

A
22
Q

What is different about the growth of rats when administered GH?

A

The bones of rats continue growing due to non-closure of the epiphysis.

23
Q

What are some characteristics that differentiate b/t acromegaly and giantism? What are some of the treatment options for either?

A
24
Q

How many AAs are in the GH peptide?

A

191 AAs

25
Q

What role does thyroid hormone play in the regulation of growth?

A

Plays a permissive role

Hypothyroidism can cause growth retardation or dwarfism

26
Q

Name 3 external factors that alter the regulation of prolactin.

A

Sleep, suckling stimulus, stress

(The triple S)

27
Q

Identify the positive and negative regulators of somatotrophs

A

Positive: GHRH

Negative: SRIF

28
Q

Describe the pathway leading to the induction of GH to the main effector of GH

A
29
Q

Use one word to describe the secretion of GH.

A

Pulsatile/episodic

30
Q

What are some conditions that upregulate SRIF, which downregulates the action of somatotrophs?

A

Galphai (decreased cAMP and decreased Ca++)

31
Q

Describe the positive and negative feedback loops mediated by GH throughout the GH cascade.

A
32
Q

How role does insulin play in the regulation of growth?

A

Deficiency has catabolic effects

Very important in utero (maternal diabetes => fetal macrosomy, insulin resistance => leprechaunism)

33
Q

Describe the cascade leading to prolactin production and the feedback loops.

A
34
Q
A
35
Q

What are some of the mutations associated with panhypopituitarism and dwarfism? What are some treatment methods?

A
36
Q

Identify some of the trophic hormones and feedback mechanisms.

A