ABSTRACT
Background: glucagons - like peptide-] [7-36] amide [GLP-1] is the main product of the glucagon gene expression in intestinal L cells. GLP-1 is released from the intestine into the circulation in response to the ingestion of food and is the most potent stimulator of glucose-induced insulin secretion. GLP-1 receptors have also been detected in discrete areas of rat brain and intracerebral ventricular injection ofGLP-1 has been shown to inhibit feeding in fasted rats
Methods and Materials: this study is an in vitro study. Used rats are male and their weight is 200 to 220 grams and each group has 7 rats. In this study HPLC techniques were employed to evaluate the effects of GLP-1 on monoamine metabolism in rat brain as a neuropeptide. Synaptosoms were prepared from homogenates of combined hypothalamus and brain stem from rats in each group. The synaptosomal pellets incubated for 15 minutes in ashaker bath at 3 7 C. The effect ofGLP-1 on Synaptosoms was tested by adding 50 pL qj"GLP-1 5x10-7 M to the incubation medium. For this group a control group was prepared by adding normal saline instead of GLP-1. The data were analyzed by T- test
Results: CLP-I decreased levels of serotonin [5-HT] by 20% [P<0. 05] after 15 minutes of incubation with combined hypothalamus and brain stem Synaptosoms. Level of 5- hydroxyindolacetic acid [5-HIAA], the principal metabolite of 5-HT, and tryptophan, the amino acid precursor of 5-HT decreased by 21% and 37 %[ P<0.05] respectively. Gamma-Aminobutyric acid [GABA] and its amino acid precursor glutamic acid [Glu] were both quantities at the same conditions as above, but an operculum derivatization HPLC technique was used. The increase levels of GABA [14%] and Glu [6%] by GLP-1 was not significant
Conclusions: the results suggest that decreased synaptosomal levels of 5-HT and 5-HIAA caused by GLP-1 are due to diminished availability of' tryptophan by the neuropeptide
ABSTRACT
Cell-mediated immunity [CMI] plays an important role in resistance against leishmaniasis. Delayed-type hypersensitivity [DTH] reaction measured by skin testing is a practical method of CMI and is used as an aid to diagnosis and for epidemiological assessment of exposure to leishmanial infection. Skin testing in leishmaniasis, generally known as Montenegro or leishmanin test, requires a standard antigen. At present no uniform and standard leishmanin is available for skin testing in leishmaniasis. The present work describes the preparation and testing of an antigen from Leishmania major using standard conditions. Three dilutions of this antigen were tested in recovered individuals in an endemic area in Iran. The results obtained showed that leishmanin preparation exhibited high specificity and sensitivity, and strong potency