ALTERATIONS IN TIMING OF SECRETION OF LUTEINIZING HORMONE AND INTERACTION WITH PROLACTIN IN TEMPORAL LOBE EPILEPSY IN MEN
Abstract number :
3.059
Submission category :
Year :
2002
Submission ID :
1990
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
Mark Quigg, Martin Straume, Ginger Leonard, Laurie Hull, William Evans, Johannes D. Veldhuis, Edward H. Bertram. Neurology, University of Virginia, Charlottesville, VA; Internal Medicine, Endocrinology, University of Virginia, Charlottesville, VA; Biology
RATIONALE: To investigate chronic and postictal alterations in hormonal secretion and circadian timing in limbic epilepsy.
Mesial temporal lobe epilepsy (MTLE) has been associated with abnormalities of reproductive physiology, but the mechanisms of hormonal dysregulation are not clear. The acute impact of seizures could alter hypothalamic function, represented by the downstream secretion of luteinizing hormone (LH) and its interaction with prolactin (PRL). Previous analyses revealed that postictal LH secretion is less orderly than baseline secretion patterns. The present study evaluates the interictal and postictal interaction of LH and PRL and the circadian timing of LH in MTLE.
METHODS: We characterized LH and PRL secretion in patients with MTLE during two 24 hour epochs: a interictal baseline, and a postictal interval initiated by an electrographically confirmed spontaneous seizure. Males, rather than females, in these pilot studies studied to insure that menstrual cycles could not account for differences between epochs. Serum LH and prolactin were measured every 10 minutes. Deconvolution analysis defined hormone secretion in terms of interpulse interval, amplitude, and mass. Cross approximate entropy (XApEn) of concentration-time data quantified the interaction of LH and PRL release. The time of day of maximum hormone secretion was calculated from the cosinor estimate of grouped data. Time estimates were compared to data from 10 healthy controls.
RESULTS: Ten epileptic men completed both inter- and postictal epochs. As reported previously, means of interpulse interval, mass, and amplitude did not differ significantly between baseline and postictal epochs, although interpulse interval of LH tended to be increased postictally (75m vs 81m, paired t-test p=0.40) and PRL interpulse interval decreased postictally (75m vs 58m, p=0.06). The concentrations of LH and PRL showed no significant interactions in timing by XApEn analysis. However, seizures caused a phase advance of over 8h in the time of maximal secretion of LH (08:22[plusminus]45m SD vs 00:43[plusminus]53m). Both baseline and postictal phase of LH secretion differed from that of healthy controls (03:11[plusminus]23m).
CONCLUSIONS: In men with intractable MTLE, the pulsatile secretion of LH and PRL have no clear correspondence either at baseline or postictally, suggesting that mechanisms of dysregulation for these two hormones are dissimilar. Seizures, however induce phase shifts in the daily secretion pattern of LH. Altered timing of neuroendocrine pulse patterns may underlie other disorders of homeostasis in MTLE.
[Supported by: General Clinical Research Center at the University of VIrginia (NIH-M01RR00884, NINDSK08-02021 (MQ)]