Observations on the Ultrastructure of Luteal Cells from PMS and PMS-HCG Treated Immature Rats

Abstract

Immature rats were made to ovulate by one of the following 2 procedures: 1) a single injection of PMS [pregnant mare''s serum (4 IU)] was given on day 26, or 2) the PMS-HCG [human chorionic gonadotropin] procedure recommended by Parlow for the preparation of rats for the assay of LH [luteinizing hormone] was followed. Some of these animals were hypophysectomized on day 30. In other rats of each series the pituitary gland was removed and transplanted to the kidney capsule as an autograft, or pituitary glands from adult females were transplanted into intact animals as homografts. The deciduomata test was carried out on all animals but was positive only in those rats given the 4 III dose of PMS. No deciduomata were formed in the hypophysectomized animals nor in any animals given the PMS-HCG treatment. Luteal tissue was removed when the rats were 37 or 43 days old and was processed for electron microscopy. As compared to the inactive luteal cells of hypophysectomized rats, the active luteal cells of rats given the 4 IU dose of PMS showed a reduced amount of lipid and a higher order of development of mitochondria, smooth and granular endoplasmic reticulum and Golgi complexes. Luteal cells from the rats given the PMS-HCG treatment were similar to these active cells but showed, in addition, numerous membrane-bound granules having the morphology of proteinaceous secretory granules. It was suggested that such granules might be related to the secretion of some nonsteroidal product.