title: Female gender exacerbates respiratory depression in leptin-deficient obesity.
abstract: Obese females are less predisposed to sleep-disordered breathing and have higher serum leptin levels than males of comparable body weight. Because leptin is a powerful respiratory stimulant, especially during sleep, we hypothesized that the elevated leptin level is necessary to maintain normal ventilatory control in obese females. We examined ventilatory control during sleep and wakefulness in male and female leptin-deficient obese C57BL/6J-Lep(ob) mice, wild-type C57BL/6J mice with dietary-induced obesity and high serum leptin levels, and normal weight wild-type C57BL/6J mice. Both male and female C57BL/6J-Lep(ob) mice had depressed hypercapnic ventilatory response (HCVR) in comparison with wild-type animals. In comparison with male C57BL/6J-Lep(ob) mice, female C57BL/6J-Lep(ob) mice had reduced HCVR and respiratory drive (a ratio of tidal volume to inspiratory time) both during non-rapid eye movement (NREM) sleep and wakefulness. In contrast, the HCVR did not differ between sexes in wild-type mice during NREM sleep and wakefulness, but was lower in females during REM sleep. Thus, leptin deficiency in female obesity is even more detrimental to hypercapnic ventilatory control during wakefulness and NREM sleep than in obese, leptin-deficient males.
authors.affiliation: Department of Medicine, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland, USA. vpolotsk@welch.jhu.edu
authors.forename: V Y
authors.initials: VY
authors.lastname: Polotsky
authors.forename: J A
authors.initials: JA
authors.lastname: Wilson
authors.forename: M C
authors.initials: MC
authors.lastname: Smaldone
authors.forename: A S
authors.initials: AS
authors.lastname: Haines
authors.forename: P D
authors.initials: PD
authors.lastname: Hurn
authors.forename: C G
authors.initials: CG
authors.lastname: Tankersley
authors.forename: P L
authors.initials: PL
authors.lastname: Smith
authors.forename: A R
authors.initials: AR
authors.lastname: Schwartz
authors.forename: C P
authors.initials: CP
authors.lastname: O'Donnell
mesh_terms: D000818:Animals; D002245:Carbon Dioxide; D005260:Female; D020738:Leptin / Q000172:deficiency*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D009765:Obesity / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D012131:Respiratory Insufficiency / Q000209:etiology* / Q000503:physiopathology; D012720:Severity of Illness Index; D012737:Sex Factors
chemical_list: D020738:Leptin; D002245:Carbon Dioxide