Preoperative growth hormone (GH) peak values during a GH releasing peptide-2 test reflect the severity of hypopituitarism and the postoperative recovery of GH secretion in patients with non-functioning pituitary adenomas

• Published in: Endocrine Journal Vol. 67; no. 2; pp. 167 - 175
• Main Authors: Soga, Akimi, Fukuda, Izumi, Kobayashi, Shunsuke, Tahara, Shigeyuki, Morita, Akio, Sugihara, Hitoshi
• Format: Journal Article
• Language: English
• Published: Japan The Japan Endocrine Society 01-01-2020; Japan Science and Technology Agency
• Subjects: Adenoma; Adenoma - complications; Adenoma - diagnostic imaging; Adenoma - surgery; Adrenocorticotropic hormone; Adrenocorticotropic Hormone - deficiency; Adult; Adult growth hormone deficiency; Aged; Aged, 80 and over; Body mass index; Female; GH releasing peptide (GHRP)-2 test; Gonadotropins; Growth hormones; Growth Substances; Human Growth Hormone - deficiency; Human Growth Hormone - metabolism; Humans; Hypogonadism; Hypopituitarism; Hypopituitarism - etiology; Hypopituitarism - metabolism; Insulin-Like Growth Factor I - metabolism; Magnetic Resonance Imaging; Male; Middle Aged; Non-functioning pituitary adenomas (NFPA); Oligopeptides; Peptides; Pituitary (anterior); Pituitary Function Tests; Pituitary hormones; Pituitary Neoplasms - complications; Pituitary Neoplasms - diagnostic imaging; Pituitary Neoplasms - surgery; Postoperative Period; Preoperative Period; Prognosis; Recovery of Function; Retrospective Studies; Secretion; Severity of Illness Index; Young Adult; Adult growth hormone deficiency; GH releasing peptide (GHRP)-2 test; Non-functioning pituitary adenomas (NFPA); Hypopituitarism
• ISSN: 0918-8959; 1348-4540
• DOI: 10.1507/endocrj.EJ19-0288

Non-functioning pituitary adenoma (NFPA) is one common cause of adult growth hormone deficiency (AGHD). In Japan, a GH-releasing peptide (GHRP)-2 test is used to evaluate GH secretion. Although the cut-off for peak GH during a GHRP-2 test for severe AGHD is ≤9 ng/mL, severe AGHD may further diminish responses (range, nearly no-response to ≤9 ng/mL). We studied whether the peak GH responses during a GHRP-2 test could be predicted based on clinical characteristics of patients with NFPA. We compared patients with almost no-response during a GHRP-2 test with other patients considered as severe AGHD. Among the 76 patients with NFPA who were admitted to our institution, 36 patients (mean age, 61 years; male/female, n = 23/n = 13) were diagnosed with severe AGHD based on a preoperative GHRP-2 test. Based on the preoperative median peak GH concentration (2.83 ng/mL), patients were divided into two groups (<median = low or group L, n = 18; ≥median = moderate or group M, n = 18). Clinical manifestations, body mass index, severity of hypopituitarism and tumor size, volume, and extension were analyzed retrospectively. Compared with group M, group L patients were significantly older and more gonadotropin and ACTH deficient. A lower peak GH release during a GHRP-2 test was associated with a higher number of anterior pituitary hormone deficiencies across all 76 patients. Postoperatively, seven in group M and no patient in group L were assessed as having no longer severe AGHD, respectively. Preoperative peak GH concentrations assessed during a GHRP-2 test reflected the severity of hypopituitarism and the recovery of postoperative GH secretion.