It doesn't have to break into glucose--there's a response dependent on amino acids. There may be a further-down-the-road effect on insulin--in the extreme, take a total fast versus eating nothing but protein, and while production of glucose from the amino acids may be a slow process, it does provide for a higher glycogen storage in both liver and muscle, and increased fasting insulin and glucose production versus the total fast.

As Ben Bikman has shown in his video that's been going the rounds, a combination of glucose and certain amino acids will result in a greater insulin secretion than glucose alone. This is also true of fatty acids, as well as ketones. ATP production and insulin secretion are tied, and it's easy to see how addition of one of the other fuels to glucose might increase ATP production. Replacing glucose with the other fuels might decrease it, since glucose is sort of the zero-to-sixty fuel, but adding these other calorie sources is another story. Various amino acids enter the Kreb cycle at different points, maybe part of why they have differing effects on insulin secretion.