Does hypothyroidism lead to hypogonadism or vice-versa?

Usually neither: Unless you have a pituitary or head injury causing your hormonal deficiencies, hypothyroidism and hypogonadism are usually separate and unrelated. People with one of these deficiencies may be statistically more likely to develop another deficiency, but it is a small likelyhood. Very low thyroid levels, untreated, can lead to deficiencies in other hormone levels, which normalize w/thyroid replaceme.