1. A parahormonal chemical mediator of ecologic significance that is secreted, largely by an organism (usually an invertebrate) into its immediate environment (air or water); it can alter the behavior or functional activity of a second organism, often of the same species as that secreting the ectohormone.
2. A hormone secreted to the outside of the body; such as, a pheromone.

Pertaining to hormones.

1. A chemical substance, formed in one organ or part of the body and carried in the blood to another organ or part; depending on the specificity of their effects. Hormones can alter the functional activity, and sometimes the structure, of just one organ or tissue or various numbers of them.
2. A number of hormone's are formed by ductless glands, but secretin and pancreozymin, formed in the gastrointestinal tract, by definition are also hormone's.

The production or formation of hormones; hormonogenic.

1. Clinical endocrinology or the study of hormones, the endocrine system, and their role in the physiology of the body.
2. A medical specialty concerned with the diagnosis and treatment of disorders of the endocrine system.

An obsolete term meaning partial or total deprivation of hormones.

Treatment with hormones.

The production of hormones; hormonopoietic.

A hormone formed by neurosecretory cells and liberated by nerve impulses (e.g., norepinephrine).

A substance, product of ordinary metabolism, not produced for a specific purpose, that acts like a hormone in modifying the activity of some distant organ; e.g., the action of carbon dioxide on the control of breathing.

A glandular secretory product, having little or no inherent biological potency, that is converted peripherally to an active hormone.

1. An intraglandular precursor of a hormone; e.g., proinsulin.
2. An obsolete term formerly used to designate a substance developed in serum that antagonizes a specific antihormone, and thus enhances the action of the corresponding hormone.