The effects of tunicamycin on anterior pituitary hormone producing cells in the rat.

Abstract
An EM study was performed to clarify the effects of tunicamycin, a glycosylation inhibitor, on rat anterior pituitary cells. Tunicamycin (10, 50 and 100 .mu.g/250 g body wt) was i.p. injected into rats, which were sacrified 24 h later. Protein hormone-producing GH [growth hormone] and prolactin cells, and ACTH cells which are known to have a glycosylated precursor, showed no recognizable changes. TSH cells and gonadotrophs, both of which secrete glycoprotein hormones consisting of .alpha. and .beta. subunits, showed remarkable dilatation of the rough endoplasmic reticulum and decreased numbers of secretory granules. Apparently, the role of glycosylation in TSH cells and gonadotrophs may have a different biological significance from that in ACTH cells.