Description of the effects of a single gene which inhibits the normal metabolic response of newborn lambs to exogenous noradrenaline.
A group of newborn Scottish Blackface lambs previously selected for low cold resistance failed to show the normal metabolic response to subcutaneous injection of exogenous noradrenaline. A subsequent study showed this failure to be due to a single major gene. Further studies on the thermogenic and physiological responses and on the inheritance of the trait, are described here. Two intercross matings between non-responders produced responder lambs indicating that the gene is not recessive. The increases in metabolic rate and rectal temperature after injection of noradrenaline were much greater in responder than in non-responder lambs (P less than 0.001), as were the increases in heart rate and respiration rate (P less than 0.001). Dissected brown adipose tissue from non-responders was apparently normal and indistinguishable from brown adipose tissue from responders. Although there was no apparent effect of the gene on birthweight or survival, survival under normal field conditions may be affected.
Slee
J
J
AFRC Institute of Animal Physiology and Genetics Research, Edinburgh Research Station, Roslin, Midlothian.
Simpson
S P
SP
D002001:Adipose Tissue, Brown / Q000033:anatomy & histology / Q000648:ultrastructure; D000818:Animals; D000831:Animals, Newborn / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D001481:Basal Metabolism / Q000187:drug effects; D001724:Birth Weight / Q000235:genetics; D001831:Body Temperature / Q000187:drug effects; D001947:Breeding; D006339:Heart Rate / Q000187:drug effects; D007279:Injections, Subcutaneous / Q000662:veterinary; D008854:Microscopy, Electron; D009638:Norepinephrine / Q000008:administration & dosage / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects; D012119:Respiration / Q000187:drug effects; D012756:Sheep / Q000235:genetics* / Q000378:metabolism / Q000502:physiology
D009638:Norepinephrine