Why are American brand name products more expensive overseas?

I used to work for a business that would ship American products overseas, where the markups for them would be up to 2.5x the price that they are in the USA. I have also heard that in Brazil American products could sell up to 4x the value that they sell for here in the USA. Why is this? Does anyone happen to know?

I also wonder if you enter the foreign version of the website for American goods, is the price adjusted for the overseas price markup? For example if I wanted to purchase a polo jacket from the polo website, and I accessed polo through the Japanese website version, could I only see prices set for the Japanese market? Thanks for any input.