Original articles  BIOCHEMISTRY 

The Journal of Sports Medicine and Physical Fitness 2004 June;44(2):200-6

Copyright © 2009 EDIZIONI MINERVA MEDICA

language: English

Plasma leptin concentrations in lean, physically active males and females in relation to body composition and metabolic variables

Lutoslawska G. ¹, Skierska E. ², Byszerwska-Szpocinska E. ³

¹ Department of Biochemistry Academy of Physical Education Warsaw, Poland 2 Department of Biology Academy of Physical Education Warsaw, Poland 3 Department of Radioimmunology Radioisotope Centre Otwock-Swierk, Poland

Aim. It is ­well rec­og­nized ­that ­plasma ­leptin ­levels ­even ­adjusted to ­body fat are sig­nif­i­cantly ­higher in ­females ­than in ­males. Addi­tion­ally, phys­ical ­activity irre­spec­tively of sex is ­known to ­affect ­plasma ­leptin con­cen­tra­tions. How­ever, the pre­dic­tors of ­plasma ­leptin ­levels in ­males and ­females char­ac­ter­ized by sim­ilar phys­ical ­activity ­were not ­studied. The aim of the ­present ­study was to ­examine the pre­dic­tors of ­plasma ­leptin con­cen­tra­tions in ­male and ­female phys­ical edu­ca­tion stu­dents not ­engaged in any spe­cific ­sport but ­active due to oblig­a­tory ­studies’ pro­gram.
­Methods. A ­total of 36 sub­jects (17 ­males and 19 ­females) vol­un­teered to par­tic­i­pate in the ­study. ­Fasting ­blood was ­drawn ­from the ante­cu­bital ­vein for glu­cose and ­insulin deter­mi­na­tion. ­Fasting ­insulin resis­tance ­index (­FIRI) was cal­cu­lated ­from ­insulin and glu­cose ­plasma ­levels. ­Body fat was ­assessed ­using bio­electric impen­dance ­method (BIA). ­Pearson ­product-­moment cor­re­la­tions ­between log10 trans­formed ­plasma ­leptin con­cen­tra­tions and ­FIRI, fat ­mass, per­centage of ­body fat and ­lean ­body ­mass ­were cal­cu­lated. Mul­tiple regres­sion anal­ysis was per­formed to ­find the ­best ­model pre­dicting ­plasma ­leptin ­levels.
­Results. In ­males the ­only var­i­ables ­affecting ­plasma ­leptin con­cen­tra­tions ­were fat ­mass (r=0.60; p<0.01) and and the per­centage of ­body fat (r=0.49; p<0.04). In con­trast, in ­females the ­best ­model ­included fat ­mass, ­lean ­body ­mass and ­FIRI (adj. R2=0.538; p=0.002).
Con­clu­sion. The ­results of the cur­rent ­study indi­cated ­that the pre­dic­tors of ­plasma ­leptin ­levels mark­edly dif­fered in phys­i­cally ­active ­males and ­females. The ­only var­i­able pre­dicting ­plasma ­leptin con­cen­tra­tions in ­both ­males and ­females was ­body fat­ness. In ­females ­lean ­body ­mass and ­fasting ­insulin resis­tance ­index (­FIRI) ­together ­with ­body fat­ness mark­edly con­trib­uted to the vari­a­tions in ­plasma ­leptin con­cen­tra­tions.