Histological study of the liver of the lizard Tropidurus torquatusWied 1820, (Squamata: Tropiduridae)(AU)

The objective of this study was to characterize macroscopically and microscopically the liver of the collared lizard Tropidurus torquatus, using two adult females and two adult males, captured on the banks of Marambaia Isle in Sepetiba Bay in the state of Rio de Janeiro. Fragments of liver were fixed in Bouin’s liquid and submitted to routine histological techniques. Sections were cut by a rotary microtome to 5 mm thickness and stained by with HE, PAS, Gomori Trichrome and Gomori’s reticulin impregnation. The liver this lizard is a large, speckled dark brown organ composed of a right and left lobe. The gallbladder is located on the visceral surface of the right lobe. The lobules are polyhedral in shape and separated by a thin layer of interlobular connective tissue, forming trabeculae. These contain bile ducts, branches of portal vein and of hepatic artery. The hepatocytes are also polyhedric and have varied sizes. The majority of these cells have nuclei offset toward the periphery, and the cytoplasm is highly vacuolated and was not well evidenced by the histological techniques utilized. The hepatic parenchyma is supported by delicate reticular fibers surrounding hepatocytes and sinusoids. Large quantities of melano-macrophage centers are present in the parenchyma.

Demographic and metabolic characteristics of individuals with progressive glucose tolerance

We evaluated changes in glucose tolerance of 17 progressors and 62 non-progressors for 9 years to improve our understanding of the pathogenesis of type 2 diabetes mellitus. Changes in anthropometric measurements and responses to an oral glucose tolerance test (OGTT) were analyzed. We identified 14 pairs of individuals, one from each group, who were initially normal glucose tolerant and were matched for gender, age, weight, and girth. We compared initial plasma glucose and insulin curves (from OGTT), insulin secretion (first and second phases) and insulin sensitivity indices (from hyperglycemic clamp assay) for both groups. In the normal glucose tolerant phase, progressors presented: 1) a higher OGTT blood glucose response with hyperglycemia in the second hour and a similar insulin response vs non-progressors; 2) a reduced first-phase insulin secretion (2.0 ± 0.3 vs 2.3 ± 0.3 pmol/L; P < 0.02) with a similar insulin sensitivity index and a lower disposition index (3.9 ± 0.2 vs 4.1 ± 0.2 µmol·kg-1·min-1 ; P < 0.05) vs non-progressors. After 9 years, both groups presented similar increases in weight and fasting blood glucose levels and progressors had an increased glycemic response at 120 min (P < 0.05) and reduced early insulin response to OGTT (progressors, 1st: 2.10 ± 0.34 vs 2nd: 1.87 ± 0.25 pmol/mmol; non-progressors, 1st: 2.15 ± 0.28 vs 2nd: 2.03 ± 0.39 pmol/mmol; P < 0.05). Theses data suggest that β-cell dysfunction might be a risk factor for type 2 diabetes mellitus.