Lipid metabolism in regressing rat corpora lutea of pregnancy (original) (raw)
Related papers
Composition of the Lipid Droplets of the Bovine Corpus Luteum
2.Establishment and maintenance of pregnancy is dependent on progesterone synthesized by luteal tissue in the ovary. Our objective was to identify the characteristics of lipid droplets (LDs) in ovarian steroidogenic cells. We hypothesized that LDs are a major feature of steroidogenic luteal cells and store cholesteryl esters. Bovine luteal tissue was used for whole tissue analysis. Further analyses were performed on isolated ovarian steroidogenic cells: granulosa and theca cells of the follicle, and small/large luteal cells. Isolated luteal LDs were collected for lipid/protein analyses. Luteal tissue contained perilipins 2/3/5, hormone-sensitive lipase and abhydrolase domain containing 5. Luteal tissue was enriched in TGs compared to other tissues, except of adipose tissue. Large and small luteal cells were distinguished from follicular cells by the presence of LDs and LD-associated proteins. Furthermore, LDs from large luteal cells were numerous and small; whereas, LDs from small l...
Diabetes, 2007
The action of lipoprotein lipase on triglyceride-rich lipoproteins generates fatty acids that are either transported into tissues or mix with circulating free fatty acids (FFAs) via a process known as spillover. In the present study, arterial, portal vein, and hepatic vein sampling catheters were surgically placed in nine mongrel dogs. The animals were subsequently studied after a 42-h fast during infusion of [14C]oleate and a lipid emulsion containing [3H]triolein; the emulsion was used as a surrogate for the study of chylomicron metabolism. More than one-half of splanchnic [3H]triglyceride uptake occurred in the liver, and substantial fractional spillover of [3H]oleate was observed in both liver and nonhepatic tissues (∼50% each). There was a significant correlation between FFA release from nonhepatic tissues (presumably visceral fat) and nonhepatic fractional spillover (R = 0.81, P < 0.01), consistent with a model in which the rate of intracellular lipolysis influences spillov...
Diabetes, 2003
There is controversy over the extent to which fatty acids (FAs) derived from plasma free FAs (FFAs) or from hydrolysis of plasma triglycerides (TGFAs) form communal or separate pools and what the contribution of each FA source is to cellular FA metabolism. Chylomicrons and lipid emulsions were labeled with [ 3 H]triolein, injected into mice, and appearance in plasma of [ 3 H]oleic acid was estimated, either through a steadystate approach or by compartmental modeling. [ 14 C]oleic acid was included to trace plasma FFA. Eighty to 90% of triglyceride (TG) label was recovered in plasma, irrespective of tracer method or TG source. The contribution of TG lipolysis to total plasma FA turnover was 10 -20%. After infusion of [ 3 H]TG and [ 14 C]FA, the retention of these labels varied substantially among liver, adipose tissue, and skeletal and heart muscle. Retention of TG label changed during fasting in the same direction as lipoprotein lipase (LPL) activity is regulated. We propose a model that reconciles the paradoxical 80 -90% loss of TG label into plasma with LPL-directed differential uptake of TGFA in tissues. In this model, TGFAs mix locally at the capillaries with plasma FFAs, where they would lead to an increase in the local FA concentration, and hence, FA uptake. Our data indicate that a distinction between TG-derived FA and plasma FFA cannot be made. Diabetes 52:614 -620, 2003
Nutrition Research, 2002
We examined clearance rates in serum of lymph lipids collected from rats fed a diet containing one of four types of structured triglycerides containing linoleic and medium-chain fatty acids, 1) sn-1 (3) medium-chain fatty acids-sn-2 linoleic acid (MLM), 2) interesterified MLM (iMLM), 3) sn-2 mediumchain fatty acids-sn-1 (3) linoleic acid (LML), and 4) interesterified LML (iLML). Rats with permanent cannulation of thoracic duct were fed a diet containing one of the structured triglycerides and then, thoracic duct lymph was collected. The lymph was injected into the right superior vena cava in rats fed the same diet for a week. Half-life of triglyceride was significantly longer in rats injected the lymph originated from rats fed LML compared to the other groups. Half-life of retinyl palmitate, a marker of chylomicron remnant, tended to be longer in the LML group. These observations suggest that the structural differences in triglycerides containing medium-chain fatty acids and linoleic acid can alter the rate of lipid clearance in serum of rats.
Recent clinical observations have indicated that triglycerides containing medium chain fatty acids may be useful in decreasing steatorrhea associated with malabsorptive states such as pancreatic insufficiency and extrahepatic biliary tract obstruction (1, 2). This suggests that significant amounts of medium chain triglycerides may be absorbed under conditions in which there are decreased intraluminal concentrations of pancreatic enzymes or bile salts. However, few quantitative data are available regarding the intestinal hydrolysis and the rate of absorption of medium chain triglycerides as compared to long chain triglycerides.