Localization of acid phosphatase in lysosomes of pituitary folliculo-stellate cells following estrogen withdrawal from primed male rats.

Acid phosphatase was localized in lysosomes of non-granulated, folliculo-stellate pituitary cells 72 h after estrogen was withdrawn from primed male rats. The appearance of lysosomes and the accumulation of lipid droplets in folliculo-stellate cells coincide with the clearance of lipid from pituitary mammotropes. Positive identification of lysosomes supports our proposal in a previous study that folliculo-stellate cells are phagocytic.

Crystalloid inclusions in folliculostellate cells of adenohypophysis following estrogen withdrawal from primed male rats.

Crystalloid inclusions were observed within nongranulated, folliculostellate pituitary cells 72 after estrogen was withdrawn from primed male rats. Like crystalloid inclusions in macrophages reported by others, those observed in this study were associated with structures that appeared to be lysosomes. We suggest that crystalloid inclusions may be the result of phagocytosis, a function of folliculostellate cells proposed by us in a previous study.

Pulsatile release of immunoreactive luteinizing hormone (irLH) in hypophysectomized male rats.

The concentration of plasma luteinizing hormone (LH) was monitored every minute by radioimmunoassay in male rats that were either hypophysectomized, or castrated and hypophysectomized. Castrated rats showed a pulsatile fluctuation of plasma immunoreactive LH (irLH) concentration with an elevated basal level, confirming previous work. The hypophysectomized and castrated hypophysectomized rats also showed pulsatile changes in plasma irLH concentration.

A possible phagocytic role for folliculo-stellate cells of anterior pituitary following estrogen withdrawal from primed male rats.

Ultrastructural changes suggesting a phagocytic role for the nongranular folliculo-stellate cells of the anterior pituitary are investigated in estrogen-primed male rats after withdrawal of estrogen. Morphological changes in mammotropes following the removal of a subcutaneous estradiol-containing Silastic implant include the formation of intracellular lipid bodies. These lipid bodies appear to be associated with enhanced estrogen-dependent prolactin secretion in mammotropes.