Maternal manipulation of brown adipose tissue and liver development in the ovine fetus during late gestation

• Published in: British journal of nutrition Vol. 77; no. 6; pp. 871 - 883
• Main Authors: Clarke, Lynne, Bryant, Michael J., Lomax, Michael A., Symonds, Michael E.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.06.1997
• Subjects: Adaptation, Physiological; Adipose Tissue, Brown - embryology; Adipose Tissue, Brown - metabolism; Analysis of Variance; Animal Nutrition; Animals; Biological and medical sciences; Brown adipose tissue; Cold Temperature; Embryology: invertebrates and vertebrates. Teratology; Embryonic and Fetal Development; Epinephrine - metabolism; Experimental organogenesis; Female; Fetus; Fundamental and applied biological sciences. Psychology; Gestational Age; Iodide Peroxidase - metabolism; Liver; Liver - embryology; Norepinephrine - metabolism; Nutrition Disorders - metabolism; Nutrition Disorders - veterinary; Organogenesis. Physiological fonctions; Pregnancy; Sheep; Sheep Diseases - metabolism; Triiodothyronine - blood; Brown adipose tissue; Fetus; Liver; Embryonic development; Temperature; Cold; Digestive system; Environmental factor; Pregnancy; Vertebrata; Mammalia; Female; Sheep; Artiodactyla; Ungulata; Adaptation
• ISSN: 0007-1145; 1475-2662
• DOI: 10.1079/BJN19970086

We examined the effect of maternal chronic cold exposure, induced by winter-shearing ewes 4 weeks before their predicted lambing date, on brown adipose tissue (BAT) and liver development in lambs. Fetuses were sampled from under-fed (60% of energy requirements for maintenance and pregnancy of an unshorn ewe) shorn or unshorn ewes at 126,140 and 145 d of gestation. Lambs were sampled from ewes within 2 h of birth. Throughout gestation fetal body, BAT and liver weights were similar in shorn and unshorn groups. The level of GDP binding to mitochondrial uncoupling protein remained low throughout gestation, but increased dramatically after birth. Lambs born to shorn ewes possesd more mitochondrial protein and exhibited a significantly higher total thermogenic activity in BAT. Type I iodothyronine 5 deiodinas(EC 3.8.1.4) activity in BAT peaked at birth, as did hepatic iodothyronine Sdeiodinase activity and was significantly greater in lambs born to under-fed shorn ewes, which exhibited a higher plasma triiodothyronine concentration. Chronic maternal adaptations to prolonged cold exposure appear to enable pregnant ewes to compensate for the negative effects of under-feeding on fetal growth and development