TWENTY‐FOUR‐HOUR PROFILES OF GROWTH HORMONE, PROLACTIN AND CORTISOL IN THE CHRONIC VEGETATIVE STATE

Abstract

The 24-h profiles of growth hormone (GH), prolactin (PRL) and cortisol were obtained from 11 patients in the chronic vegetative state in order to gain more insight into the neuroendocrine alterations caused by widespread suprahypothalamic brain damage. Age and sex-matched normal subjects served as a control group. Patients had fewer high-amplitude GH peaks (greater than 20 mU/l: 6 peaks/24 h vs 21 peaks/24-h in controls) and a (non-significant) tendency towards higher basal GH concentrations. PRL concentrations were higher in patients (296 +/- 212 (SD) vs 120 +/- 28 mU/l). Cosinor analysis also showed that 24-h rhythmicity was preserved, but acrophases were more dispersed. A nocturnal PRL acrophase occurred in only three of 11 patients but in 10 of 11 control subjects. The number of PRL peaks was the same in patients and controls. Cortisol concentrations were also higher in patients (298.3 +/- 114.6 vs 193.6 +/- 97.4 nmol/l) with a preserved circadian rhythm. The acrophases, however, were likewise more dispersed. There was no difference in the number of cortisol peaks between patients and controls, but the mean peak duration was shorter in patients (75.4 +/- 28.1 vs 109.5 +/- 28.2 min). The stage of remission was negatively correlated with the 24-h mean and the mean peak amplitude of PRL. No patient showed a normal organization of sleep stages. On visual analysis there was no apparent association between EEG patterns and hormonal parameters. These results suggest that the endocrine hypothalamus is essentially intact in the chronic vegetative state. The observed changes may be due to an altered input from extrahypothalamic brain structures.