Thyroid Function and Insulin Secretion from the Perfused Pancreas in the Rat

The influence of thyroid function on the kinetics of glucose-induced insulin secretion from theisolated perfused rat pancreas has been studied. L-Thyroxine (L-T4) administration did not modify the immediate insulin secretory response of the perfused pancreas to glucose. L-Triiodothyronine(L-T3) treatment as well as propylthiouracil (PTU)treatment decreased the immediate insulin secretory response of the pancreas slightly. Only thyroidectomy(Tx) reduced the immediate secretory response of the pancreas significantly. L-T4and L-T3 treatmentinhibited the late phase of glucose-induced insulin secretion from the isolated perfused rat pancreas, whereas Tx and PTU treatment resulted in increased insulin secretion. D-Thyroxine (D-T4) did not affect glucose-induced insulin release from the pancreas. Concomitantly, several parameters indicative of thyroid function were determined in these animals. When changes in body weight, rectal temperature,plasma glucose, plasma cholesterol, and plasmabutanol-extractable iodine...