Maintenance of Pregnancy by Progesterone in Rabbits Castrated on the 11th Day

Allen, Willard M.; Heckel, George P.

doi:10.1152/ajplegacy.1938.125.1.31

Cited by 20 publications

(4 citation statements)

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“…Extirpation of corpora lutea interrupts pregnancy, suggesting that other ovarian cells are unable to release sufficient hor-mones to maintain gestation (16). Corpora lutea extracts which induce a progestational endometrium in castrated rabbits will maintain pregnancy to term (1,17,18). Evidence for the secretion of progesterone by ovaries without corpora lutea and Graafian follicles (37,38) suggests that, at times, the site of formation of this steroid is another ovarian compartment, perhaps the interstitial cells which are numerous and well developed in both nonpregnant and pregnant animals (14,15,35).…”

Section: Introductionmentioning

confidence: 99%

Ovarian Steroid Cells

1966

The Journal of Cell Biology

123

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The lutein cells of the rabbit exhibit fine structural variations during their life-span of 28 to 30 days. A systematic examination of the corpus luteum reveals that cellular distinctions may be recognized during the first, second, and third stages of pregnancy. The agranular endoplasmic reticulum reveals vesicular, tubular, and cisternal profiles after fixation with each of the following fixatives: glutaraldehyde, osmium tetroxide, and permanganate. The osmolality of the fixing solutions was varied with sucrose and recorded with an osmometer in order to determine the effect of osmotic concentration on the intracellular membranous profiles. It was determined that vesicles and short, branched tubules of similar structure are present in the agranular reticulum when the osmolalities are 300 to 800 milliosrnols (iso-osmotic considered 300 milliosmols). At 900 milliosmols, the vesicular or tubular lumen is obliterated. Intracellular membrane profiles do not exhibit interconversions due to hyperosmotic fixative solutions. The agranular endoplasmic reticulum is randomly distributed as short tubular profiles during the first third of pregnancy. A continuity between these membranes and irregular, electron-opaque lipid masses is evident. When physiological and histochemical data indicate that the lutein cell may be storing sterol precursors, cytological observations show that the agranular endoplasmic reticulum exists in a more organized pattern within the cytoplasmic matrix. Vesicular and short tubular, circular aggregations as well as whorled cistcrnal patterns surround the larger, less electron-opaque lipid droplets. Surface views of cisternal agranular endoplasmic reticulum exhibit tubular extensions, accentuating the continuity between these two profiles. During the progress of pregnancy, the lutein cell increases in diameter, and accumulates both lipid inclusions and aggregations of intracellular membranes. The agranular endoplasmic reticulum may be peripherally packed and arranged parallel to the cell surface during later stages. In the postpartum, degenerating lutein cell, large myelin figures are present which form from the agranular endoplasmic rcticulum. These cellular events are discussed in relation to lutein cell activity, including both secretion of product and storage of precursors.

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Section: Introductionmentioning

confidence: 99%

Ovarian Steroid Cells

1966

The Journal of Cell Biology

123

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“…The inactivity of the myometrium and its refractoriness to oxytocin during pregnancy have been shown to be due to progesterone secreted by the corpus luteum (Knaus, 1926;Allen & Corner, 1929;Allen & Heckel, 1939;Wu & Allen, 1959). Thus, the present results suggest that myometrial activity during pregnancy in the guinea-pig is either not regulated by the action of progesterone, or that the mechanism of action of progesterone in the guinea-pig differs from that in the rabbit.…”

Section: Discussionmentioning

confidence: 99%

Quantitative Changes in Myometrial Activity in the Guinea-Pig During Pregnancy

Dg¹

1971

Reproduction

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“…Respiration then decreased gradually. Progesterone can maintain pregnancy in the rab bit, but increasing amounts are needed during the last half of pregnancy (Courrier and Kehl, 1938;Allen and Heckel, 1939).…”

Section: Part II Unilateral Pregnancy Arid Relationship To Blood Flomentioning

confidence: 99%

Relationship of blood flow and progestin levels on uterine-ovarian function in pigs and rabbits

Rathmacher

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Maintenance of Pregnancy by Progesterone in Rabbits Castrated on the 11th Day

Cited by 20 publications

References 0 publications

Ovarian Steroid Cells

Ovarian Steroid Cells

Quantitative Changes in Myometrial Activity in the Guinea-Pig During Pregnancy

Relationship of blood flow and progestin levels on uterine-ovarian function in pigs and rabbits

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