Is growth hormone a protein? High School Biology

Growth hormone is a protein hormone secreted by the anterior pituitary gland, and its chemical essence is a polypeptide chain composed of 191 amino acids. The growth hormone GH mentioned in high school biology textbooks has physiological functions such as promoting bone growth, protein synthesis, and fat breakdown.

1. Chemical essence:

The molecular structure of growth hormone conforms to protein characteristics, forming a spatial conformation by connecting amino acids through peptide bonds. Its synthesis process takes place on the ribosome, following the central principles of protein biosynthesis, and it belongs to a typical endocrine protein.

2. Secretion mechanism:

The growth hormone releasing hormone GHRH secreted by the hypothalamus regulates the synthesis of growth hormone in the anterior pituitary gland, which involves protein synthesis processes such as gene expression regulation and transcription translation. In high school, the regulatory mechanism of thyroid stimulating hormone releasing hormone TRH can be analogized and understood.

3. Functional characteristics:

As a protein hormone, growth hormone acts through target cell membrane receptors and cannot directly enter the nucleus. Its functions of promoting chondrocyte proliferation and accelerating amino acid transport depend on the unique spatial conformation and signal transduction ability of the protein.

4. Detection method:

Clinical detection of growth hormone levels uses immunoassay, which utilizes the principle of antigen antibody specific binding. The basis of this detection method is the protein properties of growth hormone. The biuret reagent reaction in high school experiments can also be used to verify its protein properties.

5. Application limitations:

Due to the protein's susceptibility to strong acids, bases, or high temperatures, recombinant human growth hormone rhGH needs to be administered subcutaneously. This is consistent with the enzyme characteristics learned in high school, both reflecting the structural fragility of proteins as biomolecules. understanding the protein nature of growth hormone can help grasp the core concept of "protein functional diversity" in high school biology. It is recommended to combine case studies of insulin, hemoglobin, etc. in the textbook for comparative learning, and deepen the understanding of the unity of protein structure and function by constructing a knowledge network. Daily memory can be strengthened through model making, functional flowchart drawing, and other methods, paying attention to distinguishing the differences in the mechanisms of action between protein hormones and steroid hormones.