Ontogenetic development of pancreatic thyrotropin-releasing hormone in human foetuses and in infants

: The ontogeny of thyrotropin-releasing hormone (TRH) in pancreata of human foetuses from 15-36 weeks of gestation and of infants has been studied. TRH was detectable in the pancreas of a 15 week old foetus; a progressive increase of pancreatic TRH content was observed until the 34th week of gestation, whereas a progressive decrease was found in the late period of pregnancy and in 1 year old infants. In contrast, the pancreatic insulin content showed a progressive increase during the entire pregnancy and in the first year after birth. These data indicate that TRH and insulin have different ontogenetic patterns in the human pancreas.