Leptin receptors in human skeletal muscle.
Human skeletal muscle expresses leptin receptor mRNA; however, it remains unknown whether leptin receptors (OB-R) are also expressed at the protein level. Fourteen healthy men (age = 33.1 +/- 2.0 yr, height = 175.9 +/- 1.7 cm, body mass = 81.2 +/- 3.8 kg, body fat = 22.5 +/- 1.9%; means +/- SE) participated in this investigation. The expression of OB-R protein was determined in skeletal muscle, subcutaneous adipose tissue, and hypothalamus using a polyclonal rabbit anti-human leptin receptor. Three bands with a molecular mass close to 170, 128, and 98 kDa were identified by Western blot with the anti-OB-R antibody. All three bands were identified in skeletal muscle: the 98-kDa and 170-kDa bands were detected in hypothalamus, and the 98-kDa and 128-kDa bands were detected in thigh subcutaneous adipose tissue. The 128-kDa isoform was not detected in four subjects, whereas in the rest its occurrence was fully explained by the presence of intermuscular adipose tissue, as demonstrated using an anti-perilipin A antibody. No relationship was observed between the basal concentration of leptin in serum and the 170-kDa band density. In conclusion, a long isoform of the leptin receptor with a molecular mass close to 170 kDa is expressed at the protein level in human skeletal muscle. The amount of 170-kDa protein appears to be independent of the basal concentration of leptin in serum.
Guerra
Borja
B
Department of Physical Education, University of Las Palmas de Gran Canaria, Canary Island, Spain. borja.guerra@gmail.com
Santana
Alfredo
A
Fuentes
Teresa
T
Delgado-Guerra
Safira
S
Cabrera-Socorro
Alfredo
A
Dorado
Cecilia
C
Calbet
Jose A L
JA
D000328:Adult; D000906:Antibodies; D000918:Antibody Specificity; D015153:Blotting, Western; D002352:Carrier Proteins; D006801:Humans; D007031:Hypothalamus / Q000737:chemistry; D020738:Leptin / Q000097:blood; D008297:Male; D008970:Molecular Weight; D018482:Muscle, Skeletal / Q000737:chemistry*; D000070778:Perilipin-1; D010750:Phosphoproteins / Q000032:analysis; D020033:Protein Isoforms / Q000032:analysis; D011956:Receptors, Cell Surface / Q000032:analysis* / Q000097:blood / Q000276:immunology; D054411:Receptors, Leptin; D050151:Subcutaneous Fat / Q000737:chemistry*
D000906:Antibodies; D002352:Carrier Proteins; C515448:LEPR protein, human; D020738:Leptin; D000070778:Perilipin-1; D010750:Phosphoproteins; D020033:Protein Isoforms; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin