Effect of postnatal age and a beta(3)-adrenergic agonist (Zeneca D7114) administration on uncoupling protein-1 abundance in the lamb.
We examined the effect of time after birth and beta(3)-adrenergic agonist (Zeneca D7114) administration on uncoupling protein-1 (UCP1) abundance and thermoregulation in the lamb. Forty twin lambs, all born normally at term, were maintained at a cold ambient temperature of between 3 and 8 degrees C. At 0.5, 1.75, 5.25, 11.25 and 23.25 h after birth eight sets of twins were fed 20 ml of formula milk +/- 10 mg kg(-1) of beta(3)-adrenergic agonist, and 45 min after feeding brown adipose tissue (BAT) was sampled. Colonic temperature was measured and BAT analysed for UCP1 abundance, GDP-binding to mitochondrial protein (i.e. thermogenic activity) and catecholamine content. Colonic temperature declined between 1.25 and 6 h from 40.2 degrees C to 39.2 degrees C and then increased to 39.8 degrees C at 12 h, but increased after feeding at all ages. UCP1 abundance increased from 1.25 h after birth, to peak at 2 h after birth in controls, compared with 6 h after birth in beta(3)-adrenergic agonist-treated lambs. The level of GDP-binding to mitochondrial protein did not change significantly with age but was increased by beta(3)-adrenergic agonist treatment. The noradrenaline (norepinephrine) content of BAT increased between 1.25 and 12 h after birth, irrespective of beta(3)-adrenergic agonist administration. The total weight of perirenal BAT plus its lipid, protein and mitochondrial protein content declined over the first 6 h of life. UCP1 development continues over the first 24 h of neonatal life, and can be manipulated by beta(3)-adrenergic agonist administration. This may represent one method of improving thermoregulation in newborn lambs. Experimental Physiology (2001) 86.1, 65-70.
Bird
J A
JA
The Nightingale Institute, Division of Nursing and Midwifery, School of Life, Basic and Medical Health Sciences, Kings College, London SE1 9RT, UK.
Mostyn
A
A
Clarke
L
L
Juniper
D T
DT
Budge
H
H
Stephenson
T
T
Symonds
M E
ME
D002001:Adipose Tissue, Brown / Q000378:metabolism; D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000375:Aging / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D001831:Body Temperature / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism*; D003106:Colon / Q000502:physiology; D006153:Guanosine Diphosphate / Q000378:metabolism; D007473:Ion Channels; D007668:Kidney; D008565:Membrane Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins; D009638:Norepinephrine / Q000378:metabolism; D010642:Phenoxyacetates / Q000494:pharmacology*; D050198:Phenoxypropanolamines; D011506:Proteins / Q000378:metabolism; D012756:Sheep; D013997:Time Factors; D000071256:Uncoupling Protein 1
D000318:Adrenergic beta-Agonists; D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D010642:Phenoxyacetates; D050198:Phenoxypropanolamines; D011506:Proteins; D000071256:Uncoupling Protein 1; C071909:ICI D7114; D006153:Guanosine Diphosphate; D009638:Norepinephrine