Effects of oral bromocriptine Parlodel on the endometrium of the adult female albino rat II- an electron microscopic study

ABSTRACT

The effect of bromocriptine on the endometrial ultrastructure was studied in specimens obtained form adult rats after receiving a single daily oral dose of "Parlodel" equivalent to the human either low or high dose, for 30 consecutive days. Both doses markedly increased the thickness of the uterine epithelial lining due to focal transformation of the normal simple cuboidal or low columnar epithelium into pseudostratified or even stratified columnar epithelium. Ultrastructurally, the epithelial lining in both the control and the low dose-given animals contained only one type of epithelial cells, but only in the high dose-given animals were these cells differentiated into two types the dark and the pale cells reflecting different degree of cellular protein synthesis activity. Both the low and high doses increased the cellular content of the organelles concerned with protein synthesis. The most striking cellular ultrastructural change, in response to the low and the high doses, was the presence of intracytoplasmic non-membrane bound huge vacuoles for which the term "autolytic vacuoles" was suggested, because they started as aggregates of primary lysosomes surrounded by autolysed cytoplasm most probably due to damaged leaky lysosomal membranes. With both doses, most of the stromal cells became abnormally large with an obvious increase in the amount of cytoplasm and its content of the organelles concerned with protein synthesis, The forementioned results suggest that, at least in rats, the bromocriptine increase the endometrial cellular activity probably through an estrogenic effect