ABSTRACT
OBJECTIVE: We studied the prevalence of endocrine dysfunction in subjects with idiopathic Parkinson's disease (IPD) on newer dopaminergic agents (DA). DA are also used in endocrine hypersecretory states in small doses and we hypothesized that endocrine dysfunction was likely in IPD where DA were used in comparatively much higher dosage. PATIENTS AND METHODS: Twenty-five subjects with IPD, established on DA, were recruited to this cross-sectional study. We measured insulin-like growth factor-1, prolactin, luteinizing hormone, follicle stimulating hormone, thyroid function, oestradiol or testosterone and cortisol levels following a short synacthen test. RESULTS: We studied 18 males and 7 females, whose median age was 72 years, and whose median time from diagnosis, and duration of treatment was 27 months (interquartile range 17-45 and 13-39 months, respectively). (1) Endocrine tests were normal in 19 of 25 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. (2) The cortisol response to ACTH was normal in 24 of 25 subjects (96%). (3) 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 subjects with IPD. Their clinical significance can only be speculative currently. The cortisol response to ACTH was normal in almost all but a significant minority had suppressed prolactin levels.
ABSTRACT
OBJECTIVE: To investigate cortisol responses to adrenocorticotropic hormone during thyrotoxic (G1) and euthyroid (G2) phases in patients with Graves disease (GD) who were without adrenal autoimmunity. METHODS: Fifteen patients with GD, who were thyrotropin receptor antibody positive and 21-hydroxylase antibody negative, were recruited to this prospective pilot study. A modified short Synacthen test (SST) was performed, in which cortisol was measured every 30 minutes for 2 hours during G1 and G2. RESULTS: The median times to SST were 3 weeks (G1) and 27 weeks (G2) after diagnosis of GD. Integrated stimulated cortisol levels were significantly lower at G1 in comparison with G2: mean ± standard error of the mean for area under the curve was 78,091.6 ± 4,462.1 nmol/L (G1) versus 89,055 ± 4,434 nmol/L at 120 minutes (G2), P = .017; and for delta area under the curve was 36,309.9 ± 3,526 nmol/L (G1) versus 44,041.7 ± 2,147 nmol/L at 120 minutes (G2), P = .039. Mean cortisol levels were significantly lower for G1 versus G2 at 60, 90, and 120 minutes of the SST (P = .001 to .013). The cortisol level was abnormal in 2 patients (13%) at 30 minutes during G1 but in none during G2. There was no correlation of integrated cortisol with free thyroxine or thyrotropin receptor antibody. There was no significant difference in median adrenocorticotropic hormone level (17 versus 20.4 ng/mL at G1 and G2, respectively; P = .14). CONCLUSION: Significant attenuation of stimulated cortisol occurs in the early thyrotoxic phase in comparison with the euthyroid phase in patients with GD without adrenal autoimmunity. Clinicians treating patients with GD should have a low threshold for investigating symptoms suggestive of hypoadrenalism at times of "stress."