What is growth hormone secreted by the pituitary gland

Growth hormone is secreted by the pituitary gland. The pituitary gland is the anterior part of the pituitary gland, which mainly secretes various important hormones, including growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, follicle stimulating hormone, luteinizing hormone, and prolactin.

1. Structure of the pituitary gland:

The pituitary gland is located inside the sella turcica and accounts for 75% of the total volume of the pituitary gland. It consists of the distal part, nodular part, and middle part. The distal part is the main functional area of the pituitary gland, containing five types of endocrine cells, among which growth hormone is synthesized and secreted by growth hormone cells in eosinophils. The pituitary gland is connected to the hypothalamus through the pituitary portal system and is regulated by the release of hormones from the hypothalamus.

2. Secretion regulation mechanism:

Growth hormone secretion is regulated by the hypothalamus, with growth hormone releasing hormone promoting secretion and somatostatin inhibiting secretion. This secretion is pulsed and reaches its peak during deep sleep at night. Reduced blood sugar, exercise, stress state, and protein intake can all stimulate secretion, while elevated free fatty acids and excessive glucocorticoids can inhibit secretion.

3. physiological function:

Growth hormone promotes growth and development through direct and indirect effects. The direct effects include promoting protein synthesis, fat breakdown, and gluconeogenesis; Indirect effects promote bone and soft tissue growth by stimulating the liver to produce insulin-like growth factor-1. Insufficient secretion during childhood can lead to dwarfism, while excessive secretion can cause gigantism; Excessive secretion in adults can lead to acromegaly.

4. Detection method:

Clinically, growth hormone levels are measured through blood tests, including baseline values and stimulation tests. Common stimulation tests include insulin hypoglycemia test, arginine stimulation test, etc. Due to the pulsatile secretion of growth hormone, the significance of single detection is limited, and it needs to be comprehensively judged in combination with insulin-like growth factor-1 levels. Imaging examinations such as pituitary MRI can evaluate the structure of the pituitary gland.

5. Related diseases:

Hypofunction of the pituitary gland can lead to growth hormone deficiency, commonly seen in pituitary tumors, traumatic brain injury, etc. Growth hormone tumor is the most common functional tumor of the pituitary gland, characterized by excessive secretion. Vacuolar sella syndrome may also affect pituitary function. Childhood growth retardation should exclude growth hormone deficiency, while adult acromegaly should be screened for growth hormone tumors. Maintaining a regular sleep schedule and adequate sleep can help maintain a normal rhythm of growth hormone secretion, with the peak period of secretion occurring from 10 pm to 2 am at night. Moderate exercise, especially resistance training, can stimulate secretion, but excessive exercise can actually inhibit it. Ensure high-quality protein intake in the diet and avoid blood sugar fluctuations caused by high sugar diets. During the growth and development period of children, their height and weight curves should be regularly monitored, and any abnormalities should be promptly diagnosed and checked. Adults with unexplained facial changes, enlarged hands and feet, and other symptoms should be alert to abnormal secretion of growth hormone.