Objective: We studied the prevalence of endocrine dysfunction in subjects with idiopathic Parkinsons disease (IPD) on newer dopaminergic agents (DA). DA are used in endocrine hypersecretory states in small doses and we hypothesized that endocrine dysfunction was likely in IPD where DA was used in comparatively much higher dosage.
Patients and methods: 25 subjects with IPD on DA for were recruited to this cross-sectional study. We measured IGF1, prolactin, LH, FSH, thyroid function, oestradiol or testosterone and cortisol following a short synacthen test.
Results: We studied 18 males and seven females (median age 72 years) whose median time from diagnosis, and duration of treatment was 27 months (interquartile range 1745 and1339 months respectively). i) Endocrine tests were normal in 19 subjects at recruitment. Minor abnormalities reverted to normal on repeat testing in three of six with initial abnormalities; two had persistent abnormalities; and the third subject could not be further investigated. Therefore 22 of 24 (92%) with IPD on DA therapy had normal endocrine profiles. ii) The cortisol response to ACTH was normal in 24 of 25 subjects (96%). iii) Eleven subjects (44%) had isolated PRL suppression. There were no differences between the suppressed PRL and normal PRL groups. However, a higher number of them were on non-ergoline derived DA (83 vs 31%; P<0.05).
Conclusions: We have demonstrated that newer non ergoline DA therapy caused only minimal endocrine perturbations in IPD subjects. The cortisol response to ACTH was normal in almost all but a significant minority had suppressed prolactin levels.