Metyrosine-associated endocrinological changes in pheochromocytoma and paraganglioma

Yuko Matsuo; Kenji Ashida; Ayako Nagayama; Kanoko Moritaka; Mizuki Gobaru; Junichi Yasuda; Naoyuki Ogasawara; Hirofumi Kurose; Katsuaki Chikui; Shimpei Iwata; Yukihiro Inoguchi; Nao Hasuzawa; Seiichi Motomura; Tsukasa Igawa; Masatoshi Nomura

doi:10.1530/EO-23-0006

Metyrosine-associated endocrinological changes in pheochromocytoma and paraganglioma

Endocr Oncol. 2023 Aug 29;3(1):e230006. doi: 10.1530/EO-23-0006. eCollection 2023 Jan 1.

Authors

Affiliations

¹ Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, Asahi-machi, Kurume, Fukuoka, Japan.
² Department of Urology, Kurume University School of Medicine, Asahi-machi, Kurume, Fukuoka, Japan.

Abstract

Objective: Metyrosine (alpha-methyl-para-tyrosine) effectively reduces catecholamine levels in patients with pheochromocytoma/paraganglioma. However, improvements in physiological and metabolic parameters and changes in endocrine function associated with metyrosine administration should be validated in comparison to surgery. This study was performed to confirm the effects of metyrosine on the physiological, metabolic, and endocrinological functions of patients with pheochromocytoma/paraganglioma in the perioperative period.

Design: This retrospective cohort study was performed at a single university hospital.

Methods: We included ten patients with pheochromocytoma/paraganglioma who received oral metyrosine after α-blocker therapy and consecutive surgeries. Urinary catecholamine metabolite levels and other clinical parameters were evaluated before and after metyrosine administration, and 1 week after surgery.

Results: The mean age was 53.1 ± 16.1 years. Of the ten participants (four men and six women), nine had pheochromocytoma and one had paraganglioma. The median maximum metyrosine dose was 750 mg/day. Urinary catecholamine metabolite levels significantly decreased in a dose-dependent manner after metyrosine administration. Both systolic and diastolic blood pressure significantly decreased after metyrosine and surgical treatment. Metyrosine administration significantly improved insulin sensitivity, although surgery improved the the basal insulin secretion. Additionally, serum prolactin and thyroid-stimulatory hormone levels were significantly increased by metyrosine treatment, whereas plasma renin activity was decreased.

Conclusions: Metyrosine significantly reduced catecholamines in patients with pheochromocytoma/paraganglioma and ensured the safety of the surgery. Adjustment of metyrosine administration may make surgical pretreatment more effective in achieving stabilized blood pressure and improving glucose metabolism. Endocrine parameters may manifest as the systemic effects of metyrosine administration.

Keywords: diabetes mellitus; dopamine; paraganglioma; pheochromocytoma; prolactin.