only in taxon capable of composed primarily of existence ends during endocrine process Eumetazoa fully formed stage endocrine system FBbt:00005068 NCIT:C12705 uberon AAO:0010279 MESH:D004703 GAID:439 systema endocrinum EV:0100128 UMLS:C0014136 EFO:0002969 MA:0000012 FMA:9668 Anatomical system containing glands which regulates bodily functions though the secretion of hormones.[AAO] ZFA:0001158 Anatomical system that consists of the glands and parts of glands that produce endocrine secretions and help to integrate and control bodily metabolic activity. EHDAA2:0002224 Multicellular organisms have complex endocrine systems, allowing responses to environmental stimuli, regulation of development, reproduction, and homeostasis. Nuclear receptors (NRs), a metazoan-specific family of ligand-activated transcription factors, play central roles in endocrine responses, as intermediates between signaling molecules and target genes. The NR family includes ligand-bound and orphan receptors, that is, receptors with no known ligand or for which there is no ligand Pocket. Understanding NR evolution has been further improved by comparison of several completed genomes, particularly those of deuterostomes and ecdysozoans. In contrast, evolution of NR ligands is still much debated. One hypothesis proposes that several independent gains and losses of ligand-binding ability in NRs occurred in protostomes and deuterostomes. A second hypothesis, pertaining to the NR3 subfamily (vertebrate steroid hormone receptors and estrogen related receptor), proposes that before the divergence of protostomes and deuterostomes, there was an ancestral steroid receptor (AncSR) that was ligand-activated and that orphan receptors secondarily lost the ability to bind a ligand. (...) Our analysis reveals that steroidogenesis has been independently elaborated in the 3 main bilaterian lineages (...).[well established][VHOG] endocrine glandular system TAO:0001158 EMAPA:35306 endocrine VHOG:0000098 XAO:0000158 UBERON:0000949 CALOHA:TS-1301 endocrine system reproductive system respiratory system digestive system circulatory system nervous system skeletal system musculoskeletal system biliary system exocrine system endocrine gland hematopoietic system immune system integumental system hepatobiliary system entire sense organ system non-connected functional system glandular system excretory system