Insulin sensitivity of splanchnic and peripheral adipose tissue in vivo in morbidly obese man

Lipid metabolism in omental adipose tissue during operative surgery1

“…This clearly demonstrates that the efflux of NEFA can be selectively suppressed by a glucose infusion. The fall in the arterial concentration of glycerol and NEFA was similar to those observed by others during operative [10] and postoperative period [11]. These studies had failed to show any significant change in the arterio-portal concentration difference for NEFA or glycerol.…”

“…Glycerol release by adipose tissue has been used as an index of lipolysis, as it cannot be reutilized locally due to low levels of glycerol kinase within the adipose tissue [12]. In the studies by Blackard [10] and Bjorkman [11], the arterio-venous differences in the glycerol concentration in the basal state were only 15% of the arterial values, whereas in the present study, the arterio-venous differences were 100% of the arterial value. This clearly demonstrates that our technique reflects true omental tissue metabolism, whereas portal venous sampling reflects splanchnic tissue metabolism.…”

“…In the past, visceral adipose tissue has been studied by portal venous studies either during abdominal surgery [10] or immediately in the postoperative period [11]. However, these studies may not reflect the true metabolism of visceral adipose tissue, as portal blood also is derived from splanchnic tissues.…”

Visceral fat and insulin resistance — causative or correlative?

“…Sampling from the portal vein is not easy in humans, but it has been performed in a small number of metabolic studies. In these studies, concentrations of NEFA or glycerol (another product of lipolysis) in the portal vein have been found to be close to those in arterial plasma (Hagenfeldt et al 1972;Björkman et al 1990;Blackard et al 1993). One example is the study of Blackard et al (1993): during laparotomy in obese women the portal vein was catheterized and samples taken.…”

“…In these studies, concentrations of NEFA or glycerol (another product of lipolysis) in the portal vein have been found to be close to those in arterial plasma (Hagenfeldt et al 1972;Björkman et al 1990;Blackard et al 1993). One example is the study of Blackard et al (1993): during laparotomy in obese women the portal vein was catheterized and samples taken. On the arguments above, surgical stress is one time when the high rates of lipolysis postulated for omental adipose tissue might be most evident, and yet there was no consistent difference in NEFA concentrations between arterial and hepatic portal plasma.…”