Pituitary and adrenal control of pancreatic endocrine function in the duck. II. Plasma free fatty acids, aminoacids, and insulin variations following hypophysectomy and replacement therapy with growth hormone and corticosterone.

The levels of plasma free fatty acids, aminoacids and insulin were studied in normal, hypophysectomized and beef growth hormone and/or corticosterone treated hypophysectomized ducks. Hypophysectomy decreased plasma free fatty acids, aminoacids and insulin levels; growth hormone and growth hormone + corticosterone treatments in hypophysectomized animals induced opposite changes, while corticosterone alone only increased the concentrations of plasma aminoacids and insulin. However, corticosterone enhanced the growth hormone effects on the three parameters. It is suggested that four feed-back mechanisms may be involved in the control of glucagon secretion by the anterior pituitary and the adrenal cortex : glucose-glucagon, free fatty acids-glucagon, aminoacids-glucagon and insulin-glucagon. In addition, in these experiments, insulin and glucagon always varied in opposite directions.