Incorporation of Glucose into Lipid of Perirenal and Subcutaneous Adipocytes of Rats and Sheep: Influence of Insulin

Abstract

Adipocytes were prepared by collagenase digestion of perirenal and subcutaneous fat from rats and sheep and were incubated in vitro with various concentrations of glucose and insulin. The lipogenic rate of perirenal and subcutaneous adipocytes of rats showed a quadratic response to glucose concentration. The addition of 10 nM insulin increased lipogenesis, especially at low lipogenic rates. At constant glucose concentrations, insulin concentrations up to 50 nM stimulated lipogenesis a similar amount in adipocytes from both depots. The rate of lipogenesis increased relative to cell volume in perirenal adipocytes only. The lipogenic rate of perirenal and subcutaneous adipocytes of sheep showed a positive linear response to glucose concentration, but insulin did not affect the rate of lipogenesis in adipocytes from either depot. In both rats and sheep, the rate of lipogenesis was higher in the perirenal adipocytes. It was concluded that insulin is unlikely to be the agent responsible for the differential growth rates of subcutaneous and perirenal fat depots in rats or sheep.

Circadian rhythm in wool depilation force in Merino and Merino X Border Leicester sheep

“…Logarithmic transformation (base e) of the depilation force and NAT activity data (Figs 1, 2 a), was carried out to stabilize variances, normalize the data and so validate the tests of hypotheses (see e.g. Broad, Sedcole & Ngan, 1983). Depilation force clearly follows a circadian rhythm in ewes and wethers ( Fig.…”

Use of full-fat soybeans as a source of rumen bypass polyunsaturated fatty acids for beef cattle finishing diets

“…In cattle, lipogenic activity is greater in subcutaneous adipose tissue than in perirenal adipose tissue (Hood and Allen, 1973;Loveday and Dikeman, 1980). In sheep, however, perirenal adipocytes were more active in in vitro lipogenesis than subcutaneous adipocytes (Broad et al, 1983). Also with sheep, in vivo conversion of acetate to long-chain fatty acids was greater in perirenal than subcutaneous adipose tissue (Ingle et al, 1972b).…”

“…Hood and Allen (1975) suggested that cytosolic water becomes limiting when fat cells are very large. In sheep, Broad et al (1983) found lipogenesis to increase with cell volume only in perirenal adipose tissue.…”