Proceedings of The Physiological Society

The Royal Society (ME 2012) (2012) Proc Physiol Soc 29, PC23

Poster Communications

Identification of a clavicular brown adipose tissue depot in the sheep

M. Pope1, M. Birtwistle1, H. Budge1, M. Symonds1

1. Nottingham University, Notitngham, United Kingdom.

Multiple evidence from human studies indicates that the primary sites for brown adipose tissue in humans are the bilateral clavicular depots [1]. In this study we aimed to identify an analogous region in the young sheep in order to profile changes in gene expression of critical brown (e.g. uncoupling protein (UCP)1) and white (e.g. RIP 140) adipose tissue markers during early life[2]. These were compared with perirenal-abdominal adipose tissue which represents the major fat depot in young sheep. Methods: Four triplet-bearing mothers were entered into the study and a randomly selected triplet euthanased with an intra-venous injection of barbiturate at 1, 7 or 28 days of age for adipose tissue sampling. All procedures were conducted with Home Office Approval under UK legislation. Gene expression for target genes was determined by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Their relative expression was calculated using the ΔΔCt method, relative to the geometric mean of 2 reference genes (18S and RPL19) and expressed in arbitrary units. Data are presented as mean ± SE and the effect of age assessed by ANOVA. Results: As expected gene expression of UCP1 in perirenal adipose tissue significantly decreased with age (1d: 0.744±0.133: 28d: 0.004±0.001 (p<0.001)) and this was accompanied by comparable trends in DIO2 and PDK4 within the clavicular depot. In addition, there was an increase in gene expression of RIP140 with age in both the perirenal and clavicular depots (1d: 0.22±0.03: 28d: 0.76±0.11 (p<0.01)). Conclusion: Our study shows that in the sheep during early life the changes in gene expression with the clavicular adipose tissue expression are very similar to those seen within the perirenal depot of the same animals. Taken together these are indicative of a brown depot transforming to become white or possibly a beige depot, in accord with recent suggestions in adult humans [3]. The young sheep may, therefore, provide a novel model for examining the developmental process of adipose transformation in early life.

Where applicable, experiments conform with Society ethical requirements