Effect of Dopamine Agonist (Lergotrile Mesylate) Therapy on Twenty-Four Hour Secretion of Prolactin in Treated Parkinson's Disease*

Abstract

Plasma PRL was measured at 20-min intervals in six patients with Parkinson's disease under various treatment protocols. In addition, 24-h mean GH levels were measured. The results of these studies showed that two untreated patients with Parkinson's disease had normal 24-h mean PRL levels with the normal increase during sleep. During chronic treatment with L-dopa-carbidopa (Sinemet), the 24-h PRL level was 12.8 +/- 4.9 ng/ml (mean +/- SD) and there was persistence of augmented PRL secretion during sleep. The 24-h mean GH level ranged from 1.5-4.4 ng/ml, with a mean of 2.5 ng/ml. The addition of a dopamine agonist (Lergotrile mesylate) resulted in a significant (P less than 0.01) suppression of the 24-h mean PRL levels and abolition of the normal sleep augmentation after 2 weeks of therapy. This suppression was maintained in one patient who was restudied 4 months after the addition of dopamine agonist therapy to L-dopa-carbidopa. The 24-h mean GH levels did not change significantly after the addition of the dopamine agonist when compared to L-dopa-carbidopa alone. These results suggest a dichotomy between the PRL and GH responses to combined L-dopa-carbidopa and dopamine agonist therapy. In addition, the preservation of normal PRL regulation in the two untreated patients with Parkinson's disease suggests that dopaminergic neurons are not universally affected in this disorder.

Dissociation of Thyrotropin and Prolactin Responsiveness to Thyrotropin Releasing Hormone Stimulation in <i>L</i><i>-</i>Dopa Treated Parkinsonian Patients

“…Turkington [11] reported a successful suppression of hPRL levels in hyperprolactinemic patients fol lowing 6 months treatment with L-dopa, whereas Malarkey et al [ 12] and Bell e\ al. [13] demonstrated an intact circadian rhythm of serum prolactin concentration in L-dopa treated parkinsonian patients.…”

Newer Dopaminergic Agents Cause Minimal Endocrine Effects in Idiopathic Parkinson's Disease

“…However, short-term dopaminergic therapy in normal humans16–18,26 showed variable effects on anterior pituitary hormones but consistent PRL suppression. Similar PRL suppression has been demonstrated in subjects with IPD on chronic dopaminergic therapy 25,27–29. A more recent study of chronic dopaminergic therapy in patients with IPD showed marked inhibition of PRL and peripheral growth hormone resistance 21…”

“…Similar PRL suppression has been demonstrated in subjects with IPD on chronic dopaminergic therapy. 25,[27][28][29] A more recent study of chronic dopaminergic therapy in patients with IPD showed marked inhibition of PRL and peripheral growth hormone resistance. 21 There were imitations to this study.…”

Prolactin and Its Altered Action in Alzheimer’s Disease and Parkinson’s Disease

“…The authors also noticed that chronic administration of Madopar induced changes in Prl responses possibly related to defective TIDA function, whereas the function of hypothalamic DA tended to be preserved after Sinemet treatment [171]. In a study on the regulation of PRL secretion, Bell et al found that 2 nontreated PD patients had a normal 24-h mean PRL concentrations and exhibited normal increases during sleep, indicating dopamine deficiency in PD does not influence all dopaminergic neurons [172][173][174].…”