Epsilon cell Epsilon cell Epsilon cells (ε-cells) are endocrine cells found in the Islets of Langerhans and produce the hormone ghrelin. They were discovered in mice. In human fetal pancreases, single epsilon cells scattered in primitive exocrine tissue were observed to start aggregating into clusters after gestational week 13. From gestational week 21, epsilon cells were observed around developing islets, forming an almost continuous layer at the rim of the islets. In adult pancreas samples, they remained localized on the mantle of the islets in different amounts. Production of ghrelin with insulin, glucagon, or somatostatin was not detected during development. Co-production with
Pineal gland why keeping rats in constant light decreased the weight of their pineals, and why pinealectomy and constant light affect ovary growth to an equal extent; this knowledge gave a boost to the then new field of chronobiology. The pineal body is labeled in these images. Pineal gland The pineal gland is a small endocrine gland in the brain of animals with backbones. The pineal gland produces melatonin, a serotonin-derived hormone which modulates sleep patterns in both circadian and seasonal cycles. The shape of the gland resembles a pine cone from which it derived its name. The pineal gland is located