--- title: "Growth Hormone (GH) | Anatomy and Physiology I" description: "Growth hormone (GH) is an anterior pituitary peptide hormone that promotes body growth, protein synthesis, and metabolism in Anatomy and Physiology I." canonical: "https://fiveable.me/anatomy-physiology/key-terms/growth-hormone-gh" type: "key-term" subject: "Anatomy and Physiology I" unit: "Unit 17" --- # Growth Hormone (GH) | Anatomy and Physiology I ## Definition Growth hormone (GH) is a peptide hormone made by the anterior pituitary that stimulates growth, protein synthesis, and metabolism. In Anatomy and Physiology I, it is a major example of hypothalamic-pituitary control. ## What It Is Growth hormone (GH) is a peptide hormone released by the anterior pituitary in response to signals from the hypothalamus. In Anatomy and Physiology I, you usually meet it as one of the main hormones that links the nervous system to the endocrine system and helps the body grow and maintain normal metabolism. GH does not act like a simple on/off switch. The hypothalamus regulates it with two opposite signals: growth hormone releasing hormone encourages GH secretion, while somatostatin inhibits it. That push and pull matters because GH levels rise and fall in pulses instead of staying constant all day. Once GH enters the bloodstream, it acts on many tissues directly and also stimulates the liver and other tissues to produce insulin-like growth factors, especially IGF-1. Those growth factors drive much of the long-term effect on bone and soft tissue growth. So when you think about GH, think of a chain: hypothalamus, anterior pituitary, circulating GH, then target tissues and growth factors. GH has two big jobs in the course. First, it supports growth by increasing protein synthesis and encouraging cells to divide and repair. That is why it comes up when you study bone growth, muscle development, and tissue repair. Second, it shifts metabolism by helping the body use fats for energy and by affecting how cells handle glucose. That metabolic effect is where many students get tripped up. GH is not just a “growth hormone” in the narrow sense. It also changes fuel use in the body, so it connects endocrine control to energy balance, exercise, and homeostasis. In a lab, case study, or diagram question, you may be asked to trace where GH is made, what controls it, and what happens when secretion is too low or too high. A good way to remember GH is that it supports growth most strongly during childhood and adolescence, but it still matters in adults for tissue maintenance and normal body composition. In the course, that makes it a bridge concept between endocrine anatomy, metabolism, and the way tissues adapt over time. ## Why It Matters Growth hormone shows up anywhere Anatomy and Physiology I asks how the body regulates growth, repair, and fuel use. It connects the hypothalamus and pituitary to target tissues, so it is one of the clearest examples of endocrine control through negative feedback and hormone signaling. GH also helps explain why bone and muscle do not just stay fixed after development. When you study bone remodeling or muscle hypertrophy, GH gives you a hormone-level explanation for why tissues can grow, repair, and adapt. It fits naturally with topics like exercise, nutrition, and tissue maintenance because it affects protein synthesis and energy metabolism. This term also helps you sort out hormone classes. GH is a peptide hormone, so it is water-soluble and works through receptors at the cell surface rather than slipping through the membrane like a steroid hormone. That comparison comes up a lot in endocrine chapters and in questions about how hormones produce their effects. ## Connections ### Pituitary Gland GH is released by the anterior pituitary, so this gland is the source you need to know first. When you trace GH on a diagram or in a feedback loop, the pituitary is the structure that turns hypothalamic signals into a hormone response in the bloodstream. ### Hypothalamus The hypothalamus controls GH with releasing and inhibiting hormones, especially GHRH and somatostatin. That makes GH a strong example of how the brain can regulate endocrine output, which is a recurring theme in Anatomy and Physiology I. ### Somatostatin Somatostatin is the main brake on GH secretion. If you are looking at a feedback diagram or hormone balance question, somatostatin helps show that endocrine control is not just about turning signals on, but also about keeping them from getting too high. ### [Anabolism](/anatomy-physiology/key-terms/anabolism) GH supports anabolic processes by encouraging protein synthesis and tissue growth. That relationship matters when you connect hormones to muscle repair, bone growth, or body composition changes after exercise or during development. ## On the AP Exam A quiz question or lab label may ask you to identify where GH is made, which gland controls it, or what effect it has on target tissues. You might also need to trace a feedback loop: the hypothalamus sends signals to the anterior pituitary, the pituitary releases GH, and GH affects growth and metabolism in the body. Case questions often use GH to test whether you can connect structure to function. For example, if a scenario describes abnormal growth, altered muscle mass, or unusual metabolism, you may need to decide whether the issue involves the pituitary, hypothalamus, or hormone action in target tissues. Diagram questions often ask you to place GH in the correct endocrine pathway and recognize that it is a peptide hormone with surface receptors. ## growth hormone (GH) vs Somatostatin GH and somatostatin are easy to mix up because they are both tied to growth hormone regulation. GH is the hormone that promotes growth and metabolism, while somatostatin inhibits GH release from the anterior pituitary. If one is the signal, the other is the brake. ## Key Takeaways - Growth hormone (GH) is a peptide hormone released by the anterior pituitary, not by the hypothalamus itself. - The hypothalamus controls GH with releasing and inhibiting signals, so GH secretion is part of a feedback loop. - GH supports growth by increasing protein synthesis and encouraging tissue repair and cell division. - GH also affects metabolism by shifting how the body uses fats and glucose for energy. - In Anatomy and Physiology I, GH is a classic example of how endocrine signals connect growth, homeostasis, and tissue maintenance. ## FAQs ### What is growth hormone (GH) in Anatomy and Physiology I? Growth hormone is a peptide hormone made by the anterior pituitary. It promotes body growth, tissue repair, and changes in metabolism, especially by supporting protein synthesis and influencing how cells use fuel. ### What controls growth hormone release? The hypothalamus controls GH release through two hormones: growth hormone releasing hormone stimulates secretion, and somatostatin inhibits it. That control keeps GH levels pulsing instead of staying fixed all day. ### How does growth hormone affect muscle and bone? GH encourages protein synthesis and cell growth, which supports muscle repair and bone growth. It also works partly through growth factors such as IGF-1, which help drive longer-term tissue building. ### Is growth hormone the same as somatostatin? No. GH is the hormone that promotes growth, while somatostatin suppresses GH release. They work together in the same regulatory pathway, but they have opposite effects. ## Related Study Guides - [17.11 Development and Aging of the Endocrine System ](/anatomy-physiology/unit-17/development-aging-endocrine-system/study-guide/9hMaPegwpYuirB8I) - [10.6 Exercise and Muscle Performance ](/anatomy-physiology/unit-10/6-exercise-muscle-performance/study-guide/CuEehw3kp5PMkVYC) - [17.3 The Pituitary Gland and Hypothalamus ](/anatomy-physiology/unit-17/3-pituitary-gland-hypothalamus/study-guide/LBytUT31lFYSlVgF) - [6.6 Exercise, Nutrition, Hormones, and Bone Tissue ](/anatomy-physiology/unit-6/6-exercise-nutrition-hormones-bone-tissue/study-guide/Vs6KNBr7M1wW5abH) - [24.1 Overview of Metabolic Reactions ](/anatomy-physiology/unit-24/1-overview-metabolic-reactions/study-guide/c1pa15omEBQZHS1Z) - [17.2 Hormones ](/anatomy-physiology/unit-17/2-hormones/study-guide/cTGVNWrSXnoRTo16) ## About This Document Canonical Fiveable pages are available as Markdown at the same path plus `.md`. - [llms.txt](https://fiveable.me/llms.txt): index of Fiveable's sections and URL patterns - [llms-full.txt](https://fiveable.me/llms-full.txt): complete subject and unit listing - [MCP server](https://fiveable.me/mcp): call Fiveable as tools instead of fetching pages (`https://fiveable.me/api/mcp`) - [MCP server for AP teachers](https://fiveable.me/mcp/teachers): a teacher's classes, assignments and AP-rubric grading (`https://fiveable.me/api/mcp/teacher`) ## Structured Data ```json {"@context":"https://schema.org","@graph":[{"@type":"LearningResource","@id":"https://fiveable.me/anatomy-physiology/key-terms/growth-hormone-gh#resource","name":"Growth Hormone (GH) | Anatomy and Physiology I","url":"https://fiveable.me/anatomy-physiology/key-terms/growth-hormone-gh","learningResourceType":"Concept explainer","educationalLevel":"AP® / High School","about":{"@id":"https://fiveable.me/anatomy-physiology/key-terms/growth-hormone-gh#term"},"audience":{"@type":"EducationalAudience","educationalRole":"student"},"dateModified":"2026-07-03T02:20:39.382Z","isPartOf":{"@type":"Collection","name":"Anatomy and Physiology I Key Terms","url":"https://fiveable.me/anatomy-physiology/key-terms"},"author":{"@type":"Organization","@id":"https://fiveable.me/editorial#content-team","name":"Fiveable Content Team","url":"https://fiveable.me/editorial","parentOrganization":{"@id":"https://fiveable.me/#organization"},"member":[{"@type":"Person","name":"Amanda DoAmaral","sameAs":["https://www.linkedin.com/in/adoamaral"]},{"@type":"Person","name":"Becky Bahr","sameAs":["https://www.linkedin.com/in/becky-bahr-b52743132"]}]},"publisher":{"@type":"Organization","name":"Fiveable","url":"https://fiveable.me"}},{"@type":"DefinedTerm","@id":"https://fiveable.me/anatomy-physiology/key-terms/growth-hormone-gh#term","name":"growth hormone (GH)","description":"Growth hormone (GH) is a peptide hormone made by the anterior pituitary that stimulates growth, protein synthesis, and metabolism. 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