Differentiation of newborn rat preadipocytes in culture: effects of insulin and dexamethasone.

A preadipocyte cell population isolated from the inguinal tissue of 3-day-old rats converts at confluence into mature adipocytes when cultured with insulin (10(-9) M). Insulin is necessary only from Day 4 postplating. If the addition of insulin is further delayed, the proportion of cells which will undergo adipose conversion decreases.

Development of insulin and epidermal growth factor receptors during the differentiation of rat preadipocytes in primary culture.

An homogeneous cell population isolated from the inguinal tissue of 3-day-old rats is able to proliferate in primary culture. In the presence of a physiological concentration of insulin (1.5 nM) it converts into cells exhibiting the morphology and the biochemical characteristics of adipocytes.

[Characterization and differentiation of rat preadipocytes in primary culture].

Using a density gradient medium, we isolated homogeneous cell populations from the inguinal tissue of 3-day old rats. In primary culture we obtained, for the first time, the differentiation of 99% of the cells in the presence of a physiological concentration of insulin (10(-9) M). This model closely mimicked the events occurring during normal mammalian adipose development, i.

Characteristics of the rat adipoblast during differentiation in culture.

In the present study, stromal vascular cells were obtained from the inguinal fat pad of 3-day-old rats and layered on a continuous density gradient (Percoll). After centrifugation, it was possible to collect three homogeneous cell populations of different densities and to grow them separately in primary culture. Upon reaching a confluent state two of them particularly (the lighter fractions) converted to adipocytes with a high frequency (90 per cent) in the presence of physiological concentration of insulin (10(-8) M).

Development under the control of insulin of lipogenic enzymes, lipoprotein lipase, isoproterenol and glucagon sensitivity in differentiating rat preadipocytes in primary culture.

In preadipose cellular fractions (I, II and III) isolated by density gradient centrifugation from the inguinal tissue of young rats, we followed the activity of fatty acid synthetase, ATP citrate lyase and lipoprotein lipase during differentiation in culture. 1.5 nM insulin when added at confluence markedly induced the activity of ATP citrate lyase and fatty acid synthetase in the cells derived from the lighter fractions (I and II).

Differentiation under the control of insulin of rat preadipocytes in primary culture. Isolation of homogeneous cellular fractions by gradient centrifugation.

Using a density gradient medium (Percoll) we succeeded in isolating homogeneous cell populations from the stromal-vascular fraction of the inguinal tissue of 3-day-old rats. In primary culture, in medium 199 supplemented with 10% fetal calf serum and 5.5 mM glucose, almost complete differentiation (90%) of these fractions was obtained for the first time in presence of a physiological concentration of insulin (10(-9) M).

Alteration, by early underfeeding, of cellular multiplication and differentiation in the inguinal fat pads of rats.

The effect of litter size on the incorporation of labeled thymidine (TdR) into DNA was studied in the stromal and the adipocyte fractions of the rat inguinal tissue. In experiment 1 the animal were kept in litters of 18 (UF) or 6 (control) from birth till 10 days. They were injected with [2-14C] TdR at day 3 and killed at 60 minutes, 1, 3 and 7 days post-injection.

Studies on cell proliferation in inguinal adipose tissue during early development in the rat.

[2-14C] Thymidine was injected into rats aged 3,5 and 10 days, and incorporation of the precursor into deoxyribonucleic acid (DNA) of the inguinal fat tissue was measured for short time periods. Using chromatographic procedures to measure the distribution of thymidine and its metabolites in the soluble fraction of the tissue, degradation of the precursor was found to be similar at all ages. The data indicate that thymidine was more rapidly utilized for DNA synthesis in 3-day-old rats than in older animals.