GH1 - Growth hormone 1 (Somatotropin) | Elisa - Clia - Antibody - Protein

Background

Growth hormone 1 (GH1), also known as somatotropin, is a peptide hormone produced by the anterior pituitary gland. GH1 is crucial for regulating growth, metabolism, and body composition. The hormone stimulates growth in almost all tissues, including bone and muscle, by promoting protein synthesis and cell division. GH1 plays a vital role in childhood growth and continues to influence metabolism and body structure throughout adulthood.

The secretion of GH1 is regulated by a complex interplay of hormones and factors, including growth hormone-releasing hormone (GHRH) and somatostatin from the hypothalamus. Other factors, such as sleep, stress, exercise, and nutrition, also influence GH1 levels. GH1 operates primarily through the growth hormone receptor (GHR), which activates intracellular signaling pathways, most notably the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway.

Protein Structure

GH1 is a single-chain polypeptide consisting of 191 amino acids with two disulfide bridges that stabilize its structure. The three-dimensional configuration of GH1 includes four alpha helices, which are essential for binding to its receptor. This binding induces a conformational change that triggers downstream signaling pathways responsible for its biological effects. The molecular weight of GH1 is approximately 22 kDa, although variant forms with slightly different weights exist due to alternative splicing and post-translational modifications.

Classification and Subtypes

GH1 belongs to the somatotropin/prolactin family of hormones, which are characterized by their role in growth and lactation. Within this family, GH1 is classified alongside its variants, which include placental growth hormone (GH2) and prolactin. GH1 variants can arise from alternative splicing of the GH1 gene or post-translational modifications, which can slightly alter the hormone's function and receptor affinity.

Function and Biological Significance

GH1 primarily stimulates growth and cell reproduction by promoting the synthesis of insulin-like growth factor 1 (IGF-1) in the liver and other tissues. IGF-1, in turn, mediates many of the growth-promoting effects of GH1, including increased cartilage formation and bone growth. GH1 also influences lipid metabolism by promoting lipolysis and reducing fat mass, and it enhances protein synthesis, contributing to muscle growth.

Moreover, GH1 has metabolic effects that include increasing glucose production in the liver and decreasing insulin sensitivity, which can affect overall glucose metabolism. These actions underscore GH1's critical role in maintaining metabolic homeostasis.

Clinical Issues

Abnormalities in GH1 secretion or action can lead to significant clinical conditions. Excess GH1 production, often due to pituitary adenomas, can result in gigantism in children and acromegaly in adults, characterized by excessive growth of bones and tissues. Conversely, GH1 deficiency can lead to growth hormone deficiency (GHD), resulting in stunted growth in children and various metabolic dysfunctions in adults.

Recombinant human GH1 is used therapeutically to treat GH1 deficiencies and certain conditions associated with short stature, such as Turner syndrome and chronic renal insufficiency. However, inappropriate use of GH1 for athletic performance enhancement or anti-aging purposes poses health risks, including increased susceptibility to diabetes, cardiovascular diseases, and musculoskeletal disorders.

Summary

Growth hormone 1 (GH1), also known as somatotropin, is a peptide hormone crucial for growth and metabolism, produced by the anterior pituitary gland. Structurally, GH1 is a single-chain polypeptide with 191 amino acids and two disulfide bridges, forming four alpha helices essential for receptor binding. It belongs to the somatotropin/prolactin family, which includes GH variants and prolactin. GH1 stimulates growth and cell reproduction primarily by promoting the synthesis of insulin-like growth factor 1 (IGF-1), which mediates many of its effects, including increased cartilage formation and bone growth. It also influences lipid metabolism, enhancing lipolysis and protein synthesis.

Clinically, GH1 abnormalities can cause conditions like gigantism, acromegaly, or growth hormone deficiency (GHD). Recombinant GH1 is used therapeutically for GH1 deficiencies and certain growth-related conditions. However, inappropriate use for performance enhancement or anti-aging can pose significant health risks. Overall, GH1 is essential for growth regulation and metabolic homeostasis.