Growth hormone and somatostatin
42,009views

00:00 / 00:00
Flashcards
Growth hormone and somatostatin
0 of 22 complete
Questions
USMLE® Step 1 style questions USMLE
0 of 3 complete
Memory Anchors and Partner Content
External References
First Aid
2024
2023
2022
2021
Acromegaly p. 343
somatostatin analogs for p. 333
somatostatin for p. 360
Carcinoid syndrome p. 354, 586
somatostatin for p. 360
Δ cells
somatostatinomas of p. 355
somatostatin production p. 378
Glucagon p. 333
somatostatin and p. 378
somatostatinomas and p. 355
Glucagonomas p. 356
somatostatin for p. 362
Growth hormone (GH) p. 338, 362
somatostatin p. 341
Insulin p. 333
somatostatin and p. 378
somatostatinomas and p. 355
Pepsinogen
somatostatin and p. 378
Somatostatin
glucagon and p. 333
hypothalamic/pituitary drugs p. 362
hypothalamic-pituitary hormones p. 332
production of p. 335
regulatory substances p. 378
secretory cell locations p. 380
Transcript
Content Reviewers
Growth hormone, also known as somatotropin, is a hormone which helps regulate the rate of growth in the body.
Secretion of growth hormone is dependent on the hypothalamic-pituitary axis.
The hypothalamus, which is a part of the brain, secretes growth hormone-releasing hormone into the hypophyseal portal system - which is a network of capillaries linking the hypothalamus to the anterior, or front part of the pituitary gland.
In the anterior pituitary, there are many different types of cells, each responsible for producing a type of hormone.
The growth hormone-releasing hormone binds to a surface protein on one of these cells, called somatotroph cells, and stimulates them to release of growth hormone.
Normally, growth hormone releasing hormone is released in a pulsatile manner, throughout the day and peaks one hour after you fall asleep, but it is also secreted in response to various forms of internal and external stimuli.
For example, the hypothalamus senses when there’s hypoglycemia, or low blood sugar, and in response it secretes growth hormone releasing hormone.
Exercise causes the adrenal glands to secrete epinephrine and that stimulates the hypothalamus to secrete growth hormone releasing hormone as well.
Also, during puberty, increased levels of estrogen and testosterone stimulate the hypothalamus to release growth hormone releasing hormone, which is responsible for the growth spurt.
Now there are a few negative feedback loops that generally control the release of growth hormone.
First, increased levels of growth-hormone-releasing hormone in the blood signals the hypothalamus to stop making more.
Second, when growth hormone reaches tissues like the liver, muscles, and bones, they make somatomedins, which are hormones that signal the anterior pituitary to stop producing growth hormone.
Summary
Growth hormone (GH) is a peptide hormone that stimulates growth, cell reproduction, and regeneration. It is also known as somatotropin and is released by the anterior pituitary gland. Somatostatin is a peptide hormone produced by the hypothalamus. It inhibits the release of GH from the anterior pituitary gland and the secretion of insulin and glucagon from the pancreas, and also reduces gastrointestinal motility.
Sources
- "Medical Physiology" Elsevier (2016)
- "Physiology" Elsevier (2017)
- "Human Anatomy & Physiology" Pearson (2018)
- "Principles of Anatomy and Physiology" Wiley (2014)
- "Growth hormone secretion during sleep" Journal of Clinical Investigation (1968)
- "Growth hormone pulsatility profile characteristics following acute heavy resistance exercise" Journal of Applied Physiology (2001)