Question

Which of the following statements concerning growth hormone is NOT true? A. Overproduction of growth hormone in adults results in acromegaly. B. It promotes growth of bone and muscle. C. It is secreted by the hypothalamus. D. A deficiency in growth hormone results in dwarfism.

Short answer

Statement C is not true.

Step-by-step solution

- Analyze Statement A

Statement A: 'Overproduction of growth hormone in adults results in acromegaly.' This statement is true because acromegaly is a condition caused by excessive secretion of growth hormone in adults.

- Analyze Statement B

Statement B: 'It promotes growth of bone and muscle.' This statement is true because one of the primary functions of growth hormone (GH) is to stimulate the growth of bone and muscle tissues.

- Analyze Statement C

Statement C: 'It is secreted by the hypothalamus.' This statement is false because growth hormone is secreted by the anterior pituitary gland, not the hypothalamus. The hypothalamus regulates the secretion of growth hormone through releasing and inhibiting hormones.

- Analyze Statement D

Statement D: 'A deficiency in growth hormone results in dwarfism.' This statement is true because a deficiency in growth hormone during childhood can lead to a condition known as dwarfism, characterized by short stature.

- Identify the Incorrect Statement

Among the given statements, only Statement C is false. The others are correct.

Key concepts

acromegaly

Acromegaly is a condition characterized by the overproduction of growth hormone (GH) in adults. This excessive secretion usually results from a benign tumor on the pituitary gland, known as a pituitary adenoma.

Overproduction of GH leads to the thickening of bones and an overgrowth of tissues, particularly noticeable in the hands, feet, and facial features. Unlike gigantism, which occurs when excess GH is present in children (leading to increased height), acromegaly affects adults who have already finished growing.

Symptoms may include:

• Enlarged hands and feet
• Facial changes such as enlarged nose and lips
• Joint pain
• Thickened skin
• Enlarged organs

Early diagnosis and treatment are crucial to manage symptoms and prevent complications. Treatments often involve removing the tumor or using medication to reduce GH production.

dwarfism

Dwarfism is a condition characterized by short stature resulting from a deficiency in growth hormone (GH) during childhood.

There are many forms of dwarfism, but the most common type related to GH deficiency is known as GH deficiency dwarfism or pituitary dwarfism. Here, the pituitary gland fails to produce enough growth hormone, leading to slower than normal growth rates.

Common features of GH deficiency dwarfism include:

• Short stature
• Normal body proportions but smaller size
• Delayed puberty
• A younger-looking face with respect to one's age

Diagnosis involves measuring GH levels with blood tests and stimulating tests. Treatment typically includes GH injections to promote growth and achieve a more average height. Early administration of GH therapy can significantly improve growth outcomes in children with GH deficiency.

anterior pituitary gland

The anterior pituitary gland, also known as the adenohypophysis, is a crucial component of the endocrine system.

Located at the base of the brain, it is often referred to as the 'master gland' because it controls the release of hormones from several other endocrine glands.

The anterior pituitary secretes several important hormones, including:

• Growth Hormone (GH) - stimulates growth of bones and muscles
• Thyroid-Stimulating Hormone (TSH) - stimulates the thyroid gland
• Adrenocorticotropic Hormone (ACTH) - stimulates the adrenal glands to produce cortisol
• Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH) - control reproductive processes
• Prolactin - stimulates milk production in breastfeeding women

The release of these hormones is tightly regulated by the hypothalamus through releasing and inhibiting hormones. For instance, the hypothalamus secretes Growth Hormone-Releasing Hormone (GHRH) to stimulate GH release and Somatostatin to inhibit GH release.

A well-functioning anterior pituitary gland is essential for growth, metabolism, and overall homeostasis. Dysfunction can lead to various disorders, such as acromegaly or dwarfism.