Check out this information from the author of "Mastering Leptin" and "The Leptin Diet", Byron Richards. Richards was the first to explain the leptin hormone in a book, and continues to be a leading expert. Also, his books are GREAT! He explains the connections between leptin, thyroid, adrenals, female hormones, and weight loss.
Anyway, here are just some of Byron Richards' articles on leptin. He actually has a weekly newsletter and podcast too.