Enzymes of delta 1-pyrroline-5-carboxylate metabolism in the camel tick Hyalomma dromedarii during embryogenesis. Purification and characterization of delta 1-pyrroline-5-carboxylate dehydrogenases.

The activity of P5C metabolizing enzymes: OAT, P5CR, PO, and P5CD, in the camel tick Hyalomma dromedarii has been followed throughout embryogenesis. The profiles of enzymatic activity showed clear differences in the four enzymes as the embryos grew older. During purification of P5CD to homogeneity the ion exchange chromatography steps lead to two separate forms (termed A and B) with different molecular weights (60,000-59,000 and 50,000-52,000 for the native and denatured enzymes, respectively), amino acid composition, Km for P5C and coenzymes, varying dehydrogenase activities with different substrate specificity when supplied with various aldehyde substrates. Both P5CD A and B exhibited sharp optima at pH 7.5. The effect of different divalent cations and competitive and noncompetitive inhibitors was examined. The changes in P5C metabolizing enzymes during embryogenesis suggest that H. dromedarii has the metabolic potential to convert ornithine into proline and glutamate.

Role of the hypoglycemic plant extract cleome droserifolia in improving glucose and lipid metabolism and its relation to insulin resistance in fatty liver.

In this work the mechanism of the hypoglycemic effect of the plant Cleome-Droserifolia (C.d.) was studied in a group of albino rats rendered glucose intolerant by tetracycline (T.) induced fatty liver, and compared with a normal control (C.) rats. The plant extract significantly suppressed the rise in peripheral blood glucose concentrations, both in the basal (fasting) state and after glucose intake. Suppression of basal blood glucose indicated a lowering effect of the plant extract on hepatic glucose output (HGO). The postprandial hypoglycemic effect of the plant extract without increasing insulin secretion was explained by; First: Potentiation of peripheral and hepatic insulin sensitivity. Second: by diminishing intestinal glucose absorption, which was evident by blunting plasma glucose levels throughout the oral glucose challenge. This plant might prove to have a promising therapeutic value in the treatment of diabetes mellitus, for besides its postprandial hypoglycemic effect, its suppression to hepatic glucose output in the fasting state is a beneficial therapeutic finding in favour of the plant as insulin is the most important drug that brings about this effect. The plant has also got a hypocholesterolemic effect more specifically on low density lipoprotein cholesterol (LDL-C) which consequently raised the high density lipoprotein cholesterol/low density lipoprotein cholesterol (HDL-C/LDL-C) ratio. This adds to its value as a protective and antiatherogenic agent.