What is the study of the pituitary's hormone system and glands generally called?

Endocrinology - the study of glands that secrete into the bloodstream rather than through a duct, so their products travel everywhere and act only on cells carrying the right receptor. That is the elegance of the system: a signal broadcast to the whole body and heard only where it matters.

It is slow where the nervous system is fast, and that division of labour is the point. Nerves fire in milliseconds and act on specific targets; hormones take seconds to days and coordinate whole-body states - growth, puberty, pregnancy, the stress response, the daily sleep cycle. The two meet at the hypothalamus, which is nervous tissue issuing hormonal orders.

The field's history is unusually direct about cause and effect, because you can remove a gland and see what fails. Insulin, thyroid extract and cortisone all came out of that approach and turned fatal conditions into managed ones. It also produced some genuinely grim episodes - human growth hormone was extracted from pituitaries taken from cadavers until the 1980s, when it emerged that some batches had transmitted Creutzfeldt-Jakob disease, and synthetic production could not arrive fast enough.