Endocrine Abstracts

Introduction: Numerous literature sources indicate the potential role of hyperprolactinemia in the development of obesity. Prolactin modulates the functional activity of several enzymes and transporters in adipose tissue and islets of Langerhans, potentially influencing fat and glucose metabolism. On the other hand, elevated prolactin level may induce eating disorders due to dysfunction of dopaminergic regulation of the CNS. We present a clinical case of a man with morbid obesity and giant prolactinoma which was successfully treated by high-dose cabergoline.

Clinical case presentation: A 30-year-old man presented with severe cephalgia, visual disturbances, hyperprolactinemia (PRL 12000 IU/l, no macroprolactinemia), endo-supra-laterosellar macroprolactinoma (31.3×25.5×25 mm). The patient was consulted by a neurosurgeon; the question about operation was resolved negatively due to high risk of surgical intervention and almost full loss of vision (OD=0 and OS=0.1). Administration of bromocriptine with maximum dose 12.5 mg/day for 3 years did not result in significant clinical or laboratory improvement. After that cabergoline therapy was started with gradually increasing doses up to 4.5 mg/week. Control MRI tomograms showed a good positive dynamics of adenoma size and prolactin level without complete normalization. After 5 years of cabergoline treatment MRI revealed ‘empty sella’. Unfortunately, visual function didn’t recover because of long period of optic nerves compression. Increase in body weight was noted before the diagnosis of prolactinoma presumably coinciding with the onset of hyperprolactinemia with no significant elevation during the further period of active treatment with dopamine agonists. At present, patient’s BMI is 50.8 kg/m², without impairment of glucose metabolism. The patient got diet instructions and initiated treatment with testosterone ethers.

Conclusion: This clinical observation illustrates potential relationships between prolactin and obesity and positive influence of dopamine agonists on fat metabolism among patients with hyperprolactinemia.