ELECTRON MICROSCOPIC OBSERVATIONS ON THE THYROID

Abstract

In all experiments guinea pigs of 180–220 gm. weight and Wistar strain rats of 140–160 gm. weight were used. Preparations of thyroid stimulating hormone (TSH) and thyroxine, supplied through the courtesy of Hoffman-La Roche A. G. Basel, Switzerland, were injected subcutaneously. Thiouracil pellets were implanted under the skin. Hypophysectomy was performed by the parapharyngeal approach. The thyroids were removed under ether anesthesia and immediately fixed for 24 hours in a 2% solution of OsO4 in buffered Tyrode at a pH of 7.5. Thereafter the pieces were rinsed for 1 hour in flowing tap water and transferred for dehydration successively into 50, 70, 96 and two changes of 100 percent ethanol, being kept for 1 hour in each. After remaining in benzol for 2 hours, the pieces were embedded in “esterwax” at 52° C. for 24 hours. Then they were kept at 5° C. for 20 hours and at –20° C. for 5 hours.