Melatonin and the pituitary-thyroid axis status in blind adults: a possible resetting after puberty
| Autor: | Carlo Carella, Venditto T, Antonio Bellastella, Criscuolo T, A. M. Sinisi, Sergio Iorio, G. Pisano, De Bellis A, Parlato F, Antonio Agostino Sinisi |
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| Přispěvatelé: | Bellastella, A, Sinisi, Antonio Agostino, Criscuolo, T, DE BELLIS, Annamaria, Carella, C, Iorio, S, Sinisi, Am, Parlato, F, Venditto, T, Pisano, G. |
| Jazyk: | angličtina |
| Rok vydání: | 1995 |
| Předmět: |
Adult
Male Thyroid Hormones endocrine system medicine.medical_specialty Adolescent Triiodothyronine Reverse Globulin Refractory period Endocrinology Diabetes and Metabolism Eye disease Thyroid Gland Thyrotropin Blindness Pituitary thyroid axis Melatonin Thyroxine-Binding Proteins Endocrinology Internal medicine medicine Humans biology business.industry Puberty Thyroid Healthy subjects medicine.disease medicine.anatomical_structure Pituitary Gland biology.protein Female business hormones hormone substitutes and hormone antagonists medicine.drug |
| Zdroj: | Scopus-Elsevier |
| Popis: | Summary OBJECTIVE Increased levels of free thyroid hormones have been previously described in prepubertal blind subjects and have been thought to be a consequence of a partial target organ refractoriness due to the early and prolonged lack of light perception. The aim of this study was to clarify whether this abnormality is permanent or transient and the interrelationships between melatonin and thyroid hormone secretion. MEASUREMENTS Total and free thyroid hormones, TSH, thyroxine-binding globulin (TBG), reverse trilodothyronine (rT3) and melatonin were measured In plasma samples obtained at 0800 h (two hours after lights-on) In a group of 11 totally (group 1) and 16 partially (group 2) blind adult patients and in 10 age-matched healthy subjects. RESULTS Both totally and partially blind patients showed melatonin levels higher than in controls (330 ± 106 pmol/l, group 1 and 361 ± 159 pmol/l, group 2, respectively; controls: 53 ± 12 pmol/l, P < 0.001 vs both groups), but fT4, fT3, T4, T3 TSH, rT3 and TBG concentrations showed no significant differences from controls. CONCLUSIONS A possible resetting of pltuitary-thyroid axis regulation can occur in blindness after puberty; variations of melatonin secretion could play a role in this. The inhibitory effect of melatonin on thyroid gland function found in animals does not seem to occur in humans. Elevated melatonin levels, both in patients with total blindness and in those with light perception only, suggest that more complex mechanisms other than light signalling are involved in the changes of melatonin secretion in blindness. |
| Databáze: | OpenAIRE |
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