title: Cardiac, skeletal muscle and serum irisin responses to with or without water exercise in young and old male rats: cardiac muscle produces more irisin than skeletal muscle.
abstract: Irisin converts white adipose tissue (WAT) into brown adipose tissue (BAT), as regulated by energy expenditure. The relationship between irisin concentrations after exercise in rats compared humans after exercise remains controversial. We therefore: (1) measured irisin expression in cardiac and skeletal muscle, liver, kidney, peripheral nerve sheath and skin tissues, as also serum irisin level in 10 week-old rats without exercise, and (2) measured tissue supernatant irisin levels in cardiac and skeletal muscle, and in response to exercise in young and old rats to establishing which tissues produced most irisin. Young (12 months) and old rats (24 months) with or without 10min exercise (water floating) and healthy 10 week-old Sprague-Dawley rats without exercise were used. Irisin was absent from sections of skeletal muscle of unexercised rats, the only part being stained being the perimysium. In contrast, cardiac muscle tissue, peripheral myelin sheath, liver, kidneys, and skin dermis and hypodermis were strongly immunoreactivity. No irisin was seen in skeletal muscle of unexercised young and old rats, but a slight amount was detected after exercise. Strong immunoreactivity occurred in cardiac muscle of young and old rats with or without exercise, notably in pericardial connective tissue. Serum irisin increased after exercise, being higher in younger than older rats. Irisin in tissue supernatants (cardiac and skeletal muscle) was high with or without exercise. High supernatant irisin could come from connective tissues around skeletal muscle, especially nerve sheaths located within it. Skeletal muscle is probably not a main irisin source.
authors.affiliation: Department of Cardiovascular Surgery, Elazig Research and Education Hospital, Elazig 23100, Turkey; Firat University, School of Medicine, Department of Anatomy, Elazig 23119, Turkey.
authors.forename: Suna
authors.initials: S
authors.lastname: Aydin
authors.affiliation: Firat University, School of Medicine, Department of Histology and Embryology, Elazig 23119, Turkey.
authors.forename: Tuncay
authors.initials: T
authors.lastname: Kuloglu
authors.affiliation: Firat University, School of Medicine, Department of Medical Biochemistry (Firat Hormone Research Groups), Elazig 23119, Turkey. Electronic address: saydin1@hotmail.com.
authors.forename: Suleyman
authors.initials: S
authors.lastname: Aydin
authors.affiliation: Dicle University, School of Medicine, Department of Cardiovascular Surgery, Diyarbakir 21280, Turkey.
authors.forename: Mehmet Nesimi
authors.initials: MN
authors.lastname: Eren
authors.affiliation: Mersin University, School of Medicine, Department of Cardiology, Mersin 33070, Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Celik
authors.affiliation: Firat University, School of Medicine, Department of Medical Biochemistry (Firat Hormone Research Groups), Elazig 23119, Turkey.
authors.forename: Musa
authors.initials: M
authors.lastname: Yilmaz
authors.affiliation: Firat University, School of Medicine, Department of Medical Biochemistry (Firat Hormone Research Groups), Elazig 23119, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Kalayci
authors.affiliation: Firat University, School of Medicine, Department of Medical Biochemistry (Firat Hormone Research Groups), Elazig 23119, Turkey; Erzincan University, School of Medicine, Department of Histology and Embryology, Erzincan 24030, Turkey.
authors.forename: İbrahim
authors.initials: İ
authors.lastname: Sahin
authors.affiliation: Department of Cardiovascular Surgery, Elazig Research and Education Hospital, Elazig 23100, Turkey.
authors.forename: Orhan
authors.initials: O
authors.lastname: Gungor
authors.affiliation: Firat University, School of Medicine, Department of Internal Medicine, Elazig 23119, Turkey.
authors.forename: Ali
authors.initials: A
authors.lastname: Gurel
authors.affiliation: Firat University, School of Medicine, Department of Anatomy, Elazig 23119, Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Ogeturk
authors.affiliation: Firat University, School of Medicine, Department of Histology and Embryology, Elazig 23119, Turkey.
authors.forename: Ozlem
authors.initials: O
authors.lastname: Dabak
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D005353:Fibronectins / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: C583676:FNDC5 protein, rat; D005353:Fibronectins
keywords: Cardiac and skeletal muscle; Irisin; Kidneys; Liver; Nerve sheath; Skin