Related Experiment Video
Updated: Jun 3, 2026

Rating L-DOPA-Induced Dyskinesias in the Unilaterally 6-OHDA-Lesioned Rat Model of Parkinson's Disease
Published on: October 4, 2021
[Development of secondary resistance to dopamine agonists in a patient with giant prolactinoma]
Abstract:
Currently conservative treatment is therapy of choice in most patients with prolactinoma. However in 10-20% of them resistance to dopamine agonists occurs. In the majority of such cases resistance is initial, and only a few patients after good primary response to dopamine agonists develop so called "secondary" resistance ("escape" from effect). Alternative method of treatment in this situation is surgery, but in case of large invasive adenoma radical removal is often not possible. Consequently, radiation therapy may be feasible. Among 306 patients with macroadenomas examined in Burdenko Neurosurgical Institute (Moscow, Russia) only 2 (0.65%) developed "secondary" resistance to dopamine. In 1 case radiation therapy allowed effective control of tumor size and decrease of prolactin level. 1 case is described in details, and histological material was analyzed meticulously. Downregulation of D2R receptors in tumor cells may be one of the possible mechanisms of resistance to dopamine agonists.
Insights
Dopamine agonist resistance in prolactinoma is rare. Radiation therapy offers an effective alternative for managing secondary resistance in macroadenomas when surgery is not feasible.
Area of Science:
- Endocrinology
- Neurosurgery
- Oncology
Background:
- Dopamine agonists are the primary treatment for prolactinoma.
- 10-20% of patients exhibit resistance to dopamine agonists, with a subset developing secondary resistance after initial response.
- Surgery may be challenging for large, invasive adenomas.
Related Concept Videos
Parkinson's Disease: Treatment
Parkinson's Disease is primarily a result of the loss of dopaminergic neurons in the substantia nigra pars compacta. The cornerstone of its...
Drugs Affecting GI Tract Motility: Dopamine Receptor Antagonists
Alterations in Muscle Tone lll
Parkinson's Disease: Overview
Parkinson Disease ll: Pathophysiology
Desensitization and Tachyphylaxis
Several...

