Identification of the thyrotrophs with the gonadotrophs in the anterior pituitaries of thyroidectomized rats.

Abstract

Along with histological examination of the anterior lobes of the pituitary of the thyroidectomized male rats at time intervals ranging from 10 to 300days, the count of all kinds of adenohypophyseal cells was made in serial sections. The gonadotrophs disappeared while the thyroidectomy cells (TX-cells) became numerous 10days after thyroidectomy. They were enlarged polygonal in shape, and positive to PAS, but not diffusely stained with Paget and Ecclestons' stain (1960). There was evidence to show that the TX-cells were not the modified cells of the typical thyrotrophs, but that derived from large chromophobes. The TX-cells were thereafter degenerated, and decreased in number from the 30th day of thyroidectomy, showing features of dark gonadotrophs of the Golgi-ring type. Some of the, TX-cells began to accumulate colloid substance in their cytoplasm and finally turned into the signet-ring-shaped castration cells which were destined to be destroyed within 300 days. The “immature gonadotrophs” rich in dense granules positive to PAS were additionally transformed from the large chromophobes and rapidly piled up in 120 300 days after thyroidectomy. Prostate weight and cell-height of the epithelia of seminal vesicles were criteria to gonadotrophin concentration in the chronic phase. These data were compatible with the quantitative increase of gonadotrophs after 30 days of thyroidectomy. According to our observation, the TX-cells, transformed into gonadotrophs in chronic phases, suggested that thyrotrophs and gonadotrophs were essentially of the cells of the same kind.