Development of endothermy in a tasmanian marsupial, Bettongia gaimardi and its response to cold and noradrenaline |
| |
Authors: | R W Rose N Kuswanti E Q Colquhoun |
| |
Institution: | (1) Zoology Department, University of Tasmania, GPO Box 252-5, Hobart, Tasmania, Australia 7001, AU;(2) Biochemistry Department, University of Tasmania, GPO Box 252C, Hobart, Tasmania, Australia 7001, AU |
| |
Abstract: | Marsupials at birth are ectothermic and gradually attain the ability to change their metabolic heat production during pouch
life. How this process occurs in the bettong has been measured on 13 pouch young from week 1 until 3 weeks after pouch vacation
(week 18). Oxygen consumption was measured at 35 °C (pouch temperature) and at 22 °C. The results at 35 °C showed an increase
in metabolic rate from week 1 until week 12 when there was a decrease to near adult levels after pouch vacation. At 22 °C
young bettongs had a lower metabolic rate (compared with measurements made at 35 °C) until week 9 after which there was an
increase above measurements made at 35 °C. Noradrenaline had little effect until week 10 after which the metabolic rate (although
measured at 35 °C) paralleled the levels measured at 22 °C. The free thyroxine level was low in early pouch life, increased
to a peak at week 12 then decreased. Thermal conductance increased until week 10 after which it decreased, reaching values
similar to those of adult bettongs by week 20. The results indicate that non-shivering thermogenesis occurs in this macropodoid
marsupial. This phenomenon may be a phylogenetic difference between macropodid and non-macropodid marsupials as also suggested
by Nicol et al. (1997).
Accepted: 19 February 1998 |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|