The nonhuman primate as a model of growth hormone physiology in the human being.
Our review confirms the close correlation of the physiology of GH secretion in the nonhuman primate and the human subject which has not been seen in any other animal model, at least from the studies available to date. Except for a discrepancy in the relationship of GH secretion during early sleep, there are no significant differences between the species that can not likely be explained by methodological differences. Even the discrepancy between nighttime GH secretion may be due to methods of studying the nonhuman subjects. But methodological problems are at the heart of the problem in primate research. Primates are expensive to buy ($800-$1200 is not unusual for an adult male), expensive to house ($2-$3 per day is customary), dangerous to work with (bodily injury and serious infections are equally worrisome to handlers), exquisitely sensitive to environmental factors (as noted above), and above all, the subject of appropriate concern from animal use committees: these factors easily explain the relative dearth of primate studies on GH physiology compared to rodent studies. Problems of handling the animals and ensuring their stable state are helped to large degree by facilities such as the Regional Primate Facilities in the United States. The studies reviewed above should clearly demonstrate that the primate model, in spite of all the difficulties involved, is invaluable in investigating physiological phenomenon impossible to pursue in the human being. But only studies offering fastidious attention to detail in this potentially unstable model of GH physiology are likely to answer more questions than they raise.