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  • Author: Alberto de Leiva x
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Alberto de Leiva, Federico Tortosa, Miguel A. Peinado, José Serrano, José Rodriguez-Espinosa and Manuel Puig-Domingo

Abstract

The concentration of melatonin and LH were determined in plasma samples obtained at 10-min intervals during 4 h of darkness (00.00-04.00 h) from 4 normal women, age 23-27 years, in the early follicular phase of the menstrual cycle and in 6 normal men, age 23-31 years. Additionally, melatonin concentration was determined in samples obtained from the men at 10-min intervals for 4 h during the day (10.00-14.00 h). A pulsatile pattern of melatonin secretion was found for all the subjects during darkness. There was no significant difference between women and men as to the number of pulses (2.8 ± 0.5 vs 5.2 ± 1.0 per 4 h), amplitude of pulses (51.3 ± 28 vs 27.2 ± 6 ng/l), concentration per 4 h (32.5 ± 13 vs 31.0 ± 5 ng/l), or apparent half-life of melatonin (19.3 ± 2.3 vs 15.3 ± 7.5 min). The mean amplitude of the melatonin pulse correlated (r = 0.863, p<0.001) with the mean melatonin concentration per 4 h. A pulsatile LH secretion pattern was found for the 10 subjects and did not correlate significantly with the melatonin secretion pattern. The results are consistent with an independent signal for the demonstrated nyctohemeral pulsatile melatonin and LH secretions.

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Federico Tortosa, Manuel Puig-Domingo, Miguel-Angel Peinado, Josep Oriola, Susan M. Webb and Alberto de Leiva

Abstract. Plasma melatonin circadian profiles were investigated in a group of 4 patients with anorexia nervosa and 4 healthy regularly cycling women. There were no differences in the mean age of both groups, whereas the anorexia nervosa patients had lower mean body weight (37.8 ± 2.0 vs 57.0 ± 4.9 kg) and body mass index (13.9 ± 1.1 vs 20.8 ± 2.0). Samples were collected every 2 h and plasma melatonin was measured by using a RIA with an iodinated tracer. Anorexia nervosa patients exhibited higher diurnal (60.7 ± 1.8 vs 25.4 ± 1.72 pmol/l, P< 0.02) and nocturnal (419.2 ± 37.4 vs 108.0 ± 33.6 pmol/l), P< 0.001) mean plasma melatonin concentrations. There were no differences in the time peak for nocturnal melatonin secretion in both groups, detected at 02.00 h. In anorexia nervosa, the melatonin circadian profile paralleled that observed in the control group, indicating that the increased melatonin values for anorexia nervosa were probably due to an enhanced secretory pineal function rather than an impaired melatonin metabolism. These results suggest a participation of the pineal gland in the pathophysiology of anorexia nervosa.

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Manuel L. Puig, Susan M. Webb, Carlos del Pozo, José Rodríguez Espinosa, Ma Jesús Martínez and Alberto de Leiva

Abstract. A 35 year old woman suffering from ACTH and prolactin (Prl) deficiency is described. Her symptoms of adrenal insufficiency appeared gradually after her first pregnancy in 1970; however, she conceived twice more and delivered healthy babies in 1972 and 1974, which she could not breast feed due to lack of milk. During an episode of pneumonia in 1977 she suffered acute adrenal insufficiency, after which she began treatment with hydrocortisone. Her pituitary reserve for TSH, GH, LH and FSH was normal, but her ACTH and Prl levels were undectable and did not respond to acute iv challenges of corticotrophin-releasing factor (CRF) and TRH, respectively. Autoantibodies, including antilactotroph titres, were negative, except for a positive pituitary immunofluorescence to ACTH. There was also no ACTH stimulation to a prolonged infusion of CRF followed by an acute iv bolus. These results, together with the gradual onset of symptoms which worsened after each pregnancy, suggest a possible autoimmune aetiology of her pituitary ACTH and Prl deficiencies.