RT Book, Section A1 Shah, Rachana A2 Zaoutis, Lisa B. A2 Chiang, Vincent W. SR Print(0) ID 1146116318 T1 Disorders of Pituitary Function T2 Comprehensive Pediatric Hospital Medicine, 2e YR 2017 FD 2017 PB McGraw-Hill Education PP New York, NY SN 9780071829281 LK accesspediatrics.mhmedical.com/content.aspx?aid=1146116318 RD 2024/03/28 AB The pituitary gland is comprised of two parts with distinct origins. The anterior pituitary is derived embryonically from Rathke’s pouch of oral ectoderm, while the posterior pituitary is of neuroectoderm origin. The pituitary gland regulates endocrine target organs, such as the adrenal gland, ovary, testis, and thyroid gland. Disorders of the pituitary and hypothalamus may therefore result in disruption of any of these hypothalamic-pituitary–target organ axes. Abnormalities in end-organ hormone release caused by pituitary dysfunction are considered “secondary,” and those caused by a hypothalamic abnormality are considered “tertiary.” For example, abnormal thyroid function caused by a decrease in pituitary thyroid stimulated hormone is considered “secondary hypothyroidism” while hypothyroidism due to deficient thyrotropin-releasing factor from the hypothalamus is “tertiary hypothyroidism.” Failure of growth and failure of sexual maturation are two common presentations of hypothalamic-pituitary disease in the pediatric population. Pituitary disorders may be genetic or acquired.