Leptin ve Diğer Hormonlar Üzerindeki Etkileri

Öz

Leptinin etkilerinin anlaşılması hayvanlarla yapılan ve önemli ipuçları bırakmaya devam eden fizyoloji, metabolizma ve hücresel sinyalizasyon deneylerinden kaynaklanmıştır. Leptin keşfedilmesinden bu yana, bazı metabolitler ve hormonlar ile çeşitli yollarla bağlantılı olmuştur. Leptin özellikle kalori kısıtlaması ve açlığa uyum sırasında hipotalamus-hipofiz fonksiyonlarını etkiler. Leptindeki düşüş tiroid hormonu, büyüme hormonu ve cinsel hormonların salgılanmasını sınırlayarak ve kortizol salınımını artırarak enerji harcamasını azaltmak için bir sinyaldir. Bazı etkiler ön hipofiz hücreleri tarafından doğrudan leptini bağlayarak meydana gelebilmektedir. Ancak, leptin sinyaline esas olarak hipotalamik çekirdek içinde yer alan reseptörler aracılık eder. Ayrıca leptin bu dokularda bulunan leptin reseptörleri aracılığıyla tiroid ve böbreküstü bezi fonksiyonlarını düzenleyebilir. Son olarak, leptin dokulardan farklı adipokinlerin salgılanmasını değiştirebilir ve adipoz doku fonksiyonu üzerine doğrudan etkide bulunabilir. Böylece leptin metabolik bir sinyal olarak, birçok endokrin sistem üzerinde önemli düzenleyici etkilere sahiptir.

Anahtar Kelimeler

• Leptin,Yağ doku,İnsulin,Hormonlar

The Effects of Leptin on Other Hormones

Abstract

Our understanding of the effects of leptin have stemmed mainly from animal studies, which continue to leave important clues of its roles in physiology, metabolism, and cell signaling. Since its discovery, leptin has been linked to various pathways with some metabolites and hormones. Leptin influences hypothalamic-pituitary function, particularly during the adaptation to caloric restriction and starvation. The fall in leptin is a signal to reduce energy expenditure by limiting thyroid hormone, growth hormone, and gonadal hormone secretion and by increasing cortisol release. The leptin signal is primarily mediated through receptors located within hypothalamic nuclei, although some effects may occur by leptin binding directly to cells of the anterior pituitary. Leptin may also regulate thyroid and adrenal gland function through leptin receptors located on these tissues. Finally, leptin has direct effects on adipose tissue function, which can alter secretion of various adipokines from the tissue. Thus leptin, as a signal of metabolic, has significant regulatory effects on many endocrine systems.

Keywords

• Leptin,Adipose tissue,Insulin,Hormones

Kaynakça

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