Final answer:
Glucagon administered intramuscularly (IM) for GI x-rays has an onset of 1-2 hours and a duration of 4-6 hours, with its primary effect being to increase blood glucose levels and relax GI muscles for diagnostic imaging.
Step-by-step explanation:
When Glucagon is administered intramuscularly (IM) for gastrointestinal (GI) x-rays, the onset of action typically begins within 1-2 hours, and the duration of its effects lasts about 4-6 hours. Glucagon is a hormone that causes the liver to release glucose into the bloodstream, elevating blood glucose levels. This increase in glucose level happens relatively quickly after administration, which makes it useful in quickly raising blood sugar levels in cases of hypoglycemia or for diagnostic purposes during medical procedures like GI x-rays, where it can help relax the stomach and intestinal muscles.
The information from Graph-A demonstrates that when Glucagon is injected, there's an initial increase in blood glucose within one hour, followed by a return to baseline after approximately 2.5 hours in normal individuals. For gastrointestinal x-rays, where a faster response is required, the usual expectation is to see Glucagon's pharmacological effects commence within the 1-2 hours timeframe and last for the duration necessary for the procedure.