| Abstract: | Adenohypophysectomy (hypox) was carried out in adult chickens in an attempt to assess what role, if any, the anterior pituitary gland plays in maintaining basal levels of plasma insulin (IRI) and avian pancreatic polypeptide (APP) both before and immediately after a fast-refeed regimen. Each bird was tube-fed 61 gms twice daily, body weights were taken daily, and blood samples drawn daily just before the second feeding. All birds were fasted for 24 hr on days 4-5, another blood sample taken, and then refed the usual gruel. Blood samples were taken at 5,15,30,90 and 180 min after refeeding. Hypox caused an immediate and sustained decrease in plasma IRI and a significant but transient increase in plasma APP which lasted 3-4 days before returning to normal; plasma glucose was marginally decreased. Refeeding resulted in a trend of less response (increase) in all three parameters studied in the hypox group. It is suggested that in chickens, hypox may lead to a release phenomenon from a normal inhibitory role which the anterior pituitary gland plays on APP release. |
