Allen Trenkle

Effect of starvation on pituitary and plasma growth hormone in rats.

Summary Growth hormone was measured by radioimmunoassay in anterior pituitaries and plasma obtained from adult male and female rats that had been fed or starved for 48, 114, and 163 hr. Starvation for 163 hr resulted in lower levels of growth hormone in plasma and pituitary of both sexes. Pituitary content and concentration of growth hormone were both increased with 48 and 114 hr of starvation and then were decreased at 163 hr in comparison with the animals fed ad libitum. The males consistently had smaller anterior pituitaries, higher concentrations of growth hormone in the piutitary, and lower levels of the hormone in plasma in comparison with females.

Immunological investigation of an insulinlike substance in the chicken egg.

Abstract The availability of chicken insulin and the development of a highly sensitive radioimmunoassay technique have allowed detection and immunological characterization of insulin in unfertilized chicken eggs. The substance was immunochemically similar to purified pancreatic chicken insulin. After gel filtration or acid-alcohol extraction, this substance retained the immunochemical characteristics of chicken insulin.

Influence of blood glucose levels on growth hormone secretion in sheep.

Summary Concentrations of plasma GH, as estimated by radioimmunoassay, did not change significantly in sheep during the 72 hr after feeding; however, the concentrations of blood glucose and plasma insulin decreased and levels of plasma FFA increased markedly. Furthermore, insulin-induced hypoglycemia was not a stimulus for GH secretion. Rapidly falling blood glucose levels from normal or hyperglycemic levels stimulated an increase in plasma GH concentration of short duration. Growth hormone disappeared from plasma with a half-life of 8.6 to 14.7 min. Growth hormone was distributed in a volume equal to 5.0% of body weight. The average GH secretion in 40-kg sheep was estimated to be 0.7 μg/kg/hr.

Solid-phase radioimmunoassay for sheep growth hormone.

Summary A procedure for solid-phase radioimmunoassay of ovine and bovine GH is described. Fasting sheep with functional rumens did not result in increased plasma GH levels. Young calves had somewhat higher levels of plasma GH than did mature cows.