Chronic Elevation of Pulsatile Luteinizing Hormone Secretion and Acute Depression of Postictal Pulse Rate and Orderliness in Temporal Lobe Epilepsy.
Abstract number :
2.044
Submission category :
Year :
2001
Submission ID :
952
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
M. Quigg, MS MD, Neurology, University of Virginia, Charlottesville, VA; J.M. Kiely, PhD, MD, Neurology, University of Virginia, Charlottesville, VA; B. Shneker, MD, Neurology, University of Virginia, Charlottesville, VA; E.H. Betram, MD, Neurology, Unive
RATIONALE: Temporal lobe epilepsy (TLE) has been associated with abnormalities of reproductive physiology, but the mechanism of hormonal dysregulation in TLE is not clear. Chronic effects of the epileptic lesion versus acute changes from seizures could alter hypothalamic function, represented by the downstream pulsatile secretion of luteinizing hormone (LH). We evaluate whether secretion of LH is altered in TLE and to determine whether seizures acutely disrupt LH secretion.
METHODS: We characterized LH secretion in terms of its temporal organization in patients with TLE during two 24 hour epochs: a preictal baseline, and a postictal epoch triggered by an electrographically-confirmed spontaneous seizure. Female subjects were studied between days 2-7 of the menstrual cycle. Serum LH and prolactin (as a positive control) were drawn every 10 minutes. Deconvolution analysis objectively defined pulsatile secretion terms of interpulse interval, peak pulse amplitude, and integrated pulse mass. Approximate entropy, a nonlinear, modeless measure of signal randomness, quantified any degradation in the orderliness in LH release. Comparisons between baseline epochs from age- and gender-matched historical healthy controls (M20, F20), and preictal epochs from epileptic subjects were made using t-tests. Comparisons among preictal and postictal epochs within epileptic patients were made using paired t-tests.
RESULTS: 16 epileptic subjects (10M:6F) completed both pre- and postictal epochs. 9 subjects had left and 7 had right temporal lobe seizures triggering postictal epochs. Mean prolactin levels were elevated 4.5 fold in the first 20 minutes postictally. Male epileptics had lower mean concentrations (5.08 vs 6.66 mIU/ml, p=0.04) and higher peak amplitudes (0.372 vs 0.177 mIU/ml/min) than healthy male controls. Similar changes were not significant in women. No significant changes in interpulse interval, mass, or pulse orderliness were seen between epileptic and control groups. Within epileptic subjects, interpulse interval increased in postictal epochs (68.5 vs 58.6 min, p=0.01), an effect more marked following right-sided seizures. Mass and amplitude of pulses were not affected. Orderliness of pulse mass decreased postictally (p=0.03), and orderliness of interpulse interval tended to increase postictally (p=0.10.
CONCLUSIONS: Patients with TLE demonstrate chronic elevations in peak pulsatile secretion of LH. Temporal lobe seizures decrease pulse rate and may induce greater disorder in subsequent LH pulsatile secretion. Temporal organization may underlie other disorders of homeostasis in TLE.
Support: EFA (JK), NIH NSK0802021 (MQ), NIH GCRC RR00847, NIH/NINDS NS25606.