Birsen KIRIM, ABDULKADİR BAYIR, Necdet SİRKECİOĞLU, N. Mevlüt ARAS

Balıklarda pineal bez ve melatonin hormonunun fonksiyonları

Melatonin veya 5-methoxy-N-acetyltryptamine, beyinde ve aynı zamanda retinada konuşlanmış olan beyin epifizindeki hücreler tarafından üretilen bir hormondur. Triptofan amino asidi veya seratoninin bir türevidir. Melatonin seviyesi arttığında genellikle seratonin azalmaktadır. Melatoninin salınımı karanlıkta teşvik edilirken, aydınlıkta bastırılmaktadır. Konuyla ilgili çalışmaların çoğu, balıklarda çevresel değişikliğe (ışık, tuzluluk, sıcaklık) tepki olarak fizyolojik ve davranışsal hareketleri düzenleyen endokrin mekanizmasını anlamaya odaklanmıştır. Balıkların fizyolojileri (büyüme ve üreme), davranışlarının (harekete ait) ışıkla kontrol edilmesi ve melatonin arasındaki kompleks ilişkiler uzun zamandan beri bilim adamlarınca araştırılmaktadır. Fakat mekanizmanın çalışması tam bilinmemektedir. Bu derleme, konu ile ilgili araştırmacılara ışık tutmak amacıyla geniş bir kaynak taraması yapılarak hazırlanmıştır.

Anahtar Kelimeler:

epifiz, balık, ışık, melatonin, pineal cisim, üreme, karanlık, çevresel etki, hormonal kontrol, hormon salınımı

Pineal gland in fish and functions of melatonin hormone

Melatonin or 5-methoxy-N-acetyltryptamine is a hormone produced by pinealocytes in the pineal gland, located in the brain, but also in the retina. It is a derivative of the amino acid tryptophan or serotonin. When melatonin levels increase, serotonin levels usually decrease. Oscillation of it is stimulated by darkness and inhibited by light. The major studies concerning with subject have been focused on the understanding of endocrine mechanisms regulating physiological and behavioural response to environmental change (light, salinity, temperature) in fish. Physiologists have been investigating about complex relations between melatonin which involved in the photoperiod in control of fish physiology (growth, reproduction) and behavior (Iocomotor activity) for a long time; but action of its mechanisms are not fully understood. This review is prepared with the aim of providing on preview to the researcher by gathering informating from various resources.

Keywords:

epiphyses, fishes, light, melatonin, pineal body, reproduction, dark, environmental impact, hormonal control, hormone secretion,

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