Traditionally, the EECs were classified by the peptide they secrete, although more recently, application of RNA sequencing has led us to know that a single EEC can produce multiple hormones within an individual, and different hormonal promoters may be active at different times (90, 91) The distribution of the different EECs across the gastrointestinal tract that is generally accepted is: Stomach: P/D1 cells (ghrelin), D cells (somatostatin), G cells (gastrin), and ECL cells (histamine)
The landmark Rudman study demonstrated that GH restoration in older men produced significant improvements in lean mass, fat mass, and skin thickness (9)
There is no penalty for moving slowly
A big part of the cost comes down to the drugs development, which involved years of rigorous clinical trials, not to mention the higher cost of manufacturing the prefilled pens versus a simpler delivery method like a pill