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Net superoxide levels: steeper increase with activity in cooler female and hotter male lizards

journal contribution
posted on 2023-05-17, 11:30 authored by Ballen, C, Healey, M, Wilson, M, Tobler, M, Erik WapstraErik Wapstra, Olsson, M
Ectotherms increase their body temperature in response to ambient heat, thereby elevating their metabolic rate. An often inferred consequence of this is an overall upregulation of gene expression and energetic expenditure, and a concomitant increased production of reactive oxygen species (e.g. superoxide) and, perhaps, a shortened lifespan. However, recent work shows that this may be a superficial interpretation. For example, sometimes a reduced temperature may in fact trigger up-regulation of gene expression. We studied temperature and associated activity effects in male and female Australian painted dragon lizards (Ctenophorus pictus) by allowing the lizards to bask for 4ƒnh versus12ƒnh, and scoring their associated activity (inactive versus active basking and foraging). As predicted, long-basking lizards (hereafter ʻhotʼ) showed heightened activity in both sexes, with a more pronounced effect in females. We then tested for sex-specific effects of basking treatment and activity levels on the increase in net levels of superoxide. In males, short-baskers (hereafter ʻcoldʼ) had significantly more rapidly decreasing levels of superoxide per unit increasing activity than hot males. In females, however, superoxide levels increased faster with increasing activity in the cold than in the hot basking treatment, and females earlier in the ovarian cycle had lower superoxide levels than females closer to ovulation. In short, males and females differ in how their levels of reactive oxygen species change with temperature-triggered activity.

History

Publication title

Journal of Experimental Biology

Volume

215

Issue

5

Pagination

731-735

ISSN

0022-0949

Department/School

School of Natural Sciences

Publisher

Company Of Biologists Ltd

Place of publication

140 Cowley Rd, Cambridge, CB4 0DL, UK

Rights statement

Copyright 2012 The Company of Biologists Ltd

Repository Status

  • Restricted

Socio-economic Objectives

Assessment and management of Antarctic and Southern Ocean ecosystems

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