Pediatrice Endocrine

A Chapter in Core Concepts of Pediatrics, 2nd Edition

• Contents
  • Overview
    • Endocrinology
    • Disorders of the Hypothalamus and Pituitary Gland
    • Diabetes insipidus
    • Syndrome of inappropriate secretion of ADH (SIADH)
    • Growth disorders
    • Measurements
    • Height and Length:
    • Body Proportions:
    • Short stature etiology
    • Normal variants
    • Pathological causes
    • Thyroid disorders
    • Hypothyroidism (low thyroid hormone secretion)
    • Hyperthyroidism (excessive thyroid hormone secretion)
    • Thyroid nodules
    • Thyroid cancer
    • Adrenal disorders (cortex and medulla)
    • Cortisol excess (or Cushing Syndrome)
    • Adrenal insufficiency
    • Congenital adrenal hyperplasia
    • Pheochromocytoma
    • Ambiguous genitalia and disorders of sexual development (DSD)
    • Klinefelter Syndrome (1 in 500-1000 live births)
    • Turner Syndrome (1 in 2500 live births) and mixed gonadal dysgenesis
    • Congenital Adrenal Hyperplasia (CAH)
    • Androgen insensitivity syndrome
    • Cryptorchidism
    • Puberty
    • Disorders of Puberty
    • Precocious puberty
    • Incomplete precocious puberty
    • Delayed puberty
    • Mineral disorders
    • Calcium homeostasis
    • Hypocalcemia
    • Hypercalcemia
    • Metabolic Bone Disease
    • Disorders of the endocrine part of pancreas
    • Glucose Homeostasis
    • Hypoglycemia
    • Diabetes Mellitus
    • Obesity: Disorders of Energy Balance
    • Pediatric Dyslipidemia
    • Polyendocrinopathies
    • Autoimmune Polyglandular Syndrome (APS-1 and APS-2) and Immunodysregulation Polyendocrinopathy Enteropathy X-linked (IPEX)
    • Multiple endocrine neoplasia (MEN1 and MEN2)
    • McCune-Albright Syndrome
    • Sources
    • Image sources

    BOOK INFO

    Disorders of the Hypothalamus and Pituitary Gland

    O f the endocrine glands, the hypothalamus and pituitary glands are of major importance since they act as the coordinating centers of the endocrine system.

    The hypothalamus is responsible for maintaining the body’s internal balance (homeostasis) by stimulating or inhibiting major bodily functions such as the heart rate and blood pressure, body temperature, fluid and electrolyte balance, appetite and body weight, sleep cycle and function of the gastrointestinal track. The hypothalamus is also considered the master regulator of the endocrine system; Regulatory hormones secreted by the hypothalamus are transported by the hypophyseal-portal system to the anterior and posterior pituitary (Figure 2), prompting the release of secondary hormones that can affect various organ functions.

    Hormones typically bind to membrane or nuclear receptors of specific target glands/organs, which in turn release hormones that exert negative feedback control on the releasing sites. (Figure 3).

    Figure 3. Example of negative (in red) feedback inhibition:
    The hypothalamus secretes releasing factors that act on the pituitary gland to stimulate the release of trophic hormones.
    Trophic hormones act then on target organs (e.g., adrenal, thyroid or gonads), which in response produce other
    hormones/signals, shutting down the production of releasing or/and trophic hormones.

    The hypothalamus secretes various hormones that are then transported to the anterior pituitary (Figure 4):

    • Corticotropin releasing hormone (CRH)
    • Growth hormone releasing hormone (GHRH)
    • Thyrotropin releasing hormone (TRH)
    • Gonadotropin releasing hormone (GnRH)
    • Somatostatin (inhibits growth hormone secretion)
    • Prolactin releasing and prolactin inhibitor hormones

    Figure 4. Overview of hypothalamic and pituitary hormones and their actions

    The pituitary gland also secretes hormones in response to hypothalamic release hormones:

    • Thyroid stimulating hormone (TSH)
    • Adrenocortical stimulating hormone (ACTH)
    • Follicle stimulating hormone (FSH)
    • Luteinizing hormone (LH)
    • Prolactin
    • Melanocyte-stimulating hormone
    • Endorphins

    Supraoptic and paraventricular nuclei of the hypothalamus also secrete hormones that are transported to the posterior pituitary to be released into the circulation. These are:

    Disorders of the hypothalamus can result in appetite, temperature and sleep disorders. As an example, hypothalamic obesity occasionally develops in response to major hypothalamic injury/damage affecting the centers of appetite regulation and energy balance. Hypothalamic obesity is characterized by an uninhibited eating disorder that often results in morbid obesity and can be associated with other obesity complications like diabetes, dyslipidemia, obstructive sleep apnea, mood disorder etc.

    Disorders of the hypothalamus and/or anterior pituitary can also result in hypopituitarism, including adrenal insufficiency (see adrenal disorders section), hypothyroidism (see thyroid disorders section), hypogonadism (see puberty and its disorders section), growth hormone deficiency (see growth disorders section) and prolactin deficiency (inability to lactate).

    Disorders of the posterior pituitary can result in diabetes insipidus and disorders pertaining to oxytocin deficiency (like inability to lactate, vaginal dryness, decreased libido etc.).

    Content ©2019. Some Rights Reserved.
    Date last modified: February 14, 2019.
    Olivia Ginnard DO and Aikaterini (Katerina) Nella MD
    Dept. of Pediatrics
    University of Texas Medical Branch
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