الفهرس 
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Abstract
The main function of the large intestine is the absorption of fluid and electrolytes forming solid fè.ces. In this process the role of the large intestine motility is mixing and propulsion of fces to the rectum (Connel, 1Q75) Segmentation and propulsion are the appropriate motor actions to perform this function (Chauve, et.. al., 1976). It has become clear recently that well organized motility patterns occur in fed as well as the fasting state. The importance of these motility patterns is apparent from the dysfunctions that occur when they are absent or disordered CChristensefl, 1981).
Several methods have been used to study large intestine motiltity such as radiology, manometric techniques, endoscopy, radioimmufloassaY of gut hormones and electro— myography (Wlngate, 1987).
The normal patterns of colonic myoelectrical activities as well as the changes that may occur in some colonic diseases that are more frequently seen in our locality as schistosomal and amoebic colitis as well as irritable bowel syndrome was studied by Ref aat,et. al. (1985). This study found that the colonic myoelectrical activities are characterized by the presence of two distinct rhythms of slow waves, high frequancy waves (7-10 cycles/mm) and low frequency waves (3-5 cycles/mm). High amplitude spikes were found to be superimposed on both slow wave rhythms. This study also found that high frequency wave percentage was significantly higher in normal subjects than in patients with irritable bowel syndrome (IBS) and schistosomal colitis. Low frequency wave percentage was significantly higher in patients with lBS and schistosomal colitis than normal subjects; and that waves were assocciated with more frequant spikes.
These authors suggested that the colonic myoelectrical activity is considered as an index of smooth muscle function and its level of excitation as measured by épike potential activity. Thus, the abnormalities of myoelectrical activity recorded in different colopathies indicate a basic disorder of smooth muscle function which reflects a characteristic of pathophysiologic change which differs from one lesion to the other. This pathophysiologic change may be caused by a disturbance of neural or humoral factors as well as altered ionic composition of the extracellular fluid.
Somatostatin is a naturally occuring polypeptide secreted by many mammalian tissues espicially the brain, the gut and the pancreas CO’Dorisio, 1979). In the gastrointestinal tract, it is secreted by D cells that are distributed all over the gut CLarsson, 1980).
Somatostatin impairs the motility of the gastro2 intestinal tract including the large intestine. The interval between migrating myo-electrical complex is increased and the transit time is also increased (krejs, 1986). Somatostatin decreases the release of many gut hormones that affect colonic motility as motilin (Bloom, et. al, 1975), vaso—active intestinal peptid (lennon,et. al., 1975), cholecystokinin pancreozymen (Larsson, eL al., 1977)
.etc.
The study of somatostatin in the commen colopathies encorintered in our locality is lacking and may underly the myoelectrical disturbances encorintered in the study of Refaat,et. al. (1Q85).
In the present study circulating somatostatin levels were studied in irritable bowel syndrome as well as the common Egyptian colopathies mainly schistosomal and amoebic colitis in a trial to find an explaint for the previous studies by Refaat,et. al.(1985). The relation of somatostatin levels to the different symptoms of colitis, which may underlie motility disturbances, was also studied.