What is the role of growth hormone (GH) provocative testing and prolactin testing in the diagnosis of hypopituitarism (panhypopituitarism)?

Updated: Jun 09, 2020
  • Author: Bernard Corenblum, MD, FRCPC; Chief Editor: Romesh Khardori, MD, PhD, FACP  more...
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Given that GH secretion is pulsatile and low in most adults through most of the day, a single low serum level cannot be interpreted, whereas a single elevated or normal serum GH level can exclude the diagnosis of GH deficiency. Best is a provocative test for GH secretion. The serum IGF-1 may be useful for GH deficiency in children but not in adults, as up to a third of adults with proven GH deficiency by provocative testing may have a normal serum IGF-1. There are various GH stimulation tests, with glucagon and hypoglycemia being the most definitive. GH-releasing hormone (GHRH) for such testing is difficult to obtain.

Prolactin deficiency can also be verified by directly measuring serum levels. As with most other pituitary hormones, secretion of prolactin is episodic; more than 1 value is necessary for diagnosis. However, testing is rarely necessary since most patients are asymptomatic, and the results are not clinically relevant unless a woman wishes to lactate.

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