Cross reference: Ligands Evolution of Hormones Receptor Evolution
Parazoa Hormones Coelenterata Hormones Coelenterata Neuropeptides
Hemichordate Hormones Protochordate Hormones
Endocrinology - NCBI Bookshelf (Wiki)
The Endocrine System (Goog)
"A hormone ... is a chemical released by a cell in one part of the body, that sends out messages that affect cells in other parts of the organism. ... It is essentially a chemical messenger that transports a signal from one cell to another."
" All multicellular organisms produce hormones ... "
"Hormones in animals are often transported in the blood. Cells respond to a hormone when they express a specific receptor for that hormone. The hormone binds to the receptor protein, resulting in the activation of a signal transduction mechanism that ultimately leads to cell type-specific responses."
"Vertebrate hormones fall into three chemical classes:
Peptide hormone - Wikipedia
"Peptide hormones and protein hormones are hormones whose molecules are peptides or proteins, respectively. The latter have longer amino acid chain lengths than the former. These hormones have an effect on the endocrine system of animals, including humans. Most hormones can be classified as either amino acid–based hormones (amine, peptide, or protein) or steroid hormones. The former are water-soluble and act on the surface of target cells via second messengers; the latter, being lipid-soluble, move through the plasma membranes of target cells (both cytoplasmic and nuclear) to act within their nuclei."
Glycoprotein - Wikipedia
"Glycoproteins are proteins that contain oligosaccharide chains (glycans) covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. Secreted extracellular proteins are often glycosylated."
Hormones that are glycoproteins include:
Neurotrophin - Wikipedia
"Neurotrophins are a family of proteins that induce the survival, development, and function of neurons. They belong to a class of growth factors, secreted proteins that are capable of signaling particular cells to survive, differentiate, or grow. Growth factors such as neurotrophins that promote the survival of neurons are known as neurotrophic factors."
Emergence and evolution of the glycoprotein hormone and neurotrophin gene families in vertebrates.
See: Amphioxus Pituitary .
Functional characterization of GH-like homolog in amphioxus reveals an ancient origin of GH/GH receptor system.
Endocrinology Full-length reference:
Wikipedia Full-length reference:
Dehydroepiandrosterone: an ancestral ligand of neurotrophin receptors.
"Based on our data, we hypothesize that early in evolution, DHEA may have acted as a nonspecific neurotrophic factor promoting neuronal survival. The interaction of DHEA with all types of neurotrophin receptors offers new insights into the largely unidentified mechanisms of its actions on multiple tissues and organs known to express neurotrophin receptors."