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Luteotropic actions of placental lactogens at midpregnancy in the mouse.
- Source :
-
Endocrinology [Endocrinology] 1995 Sep; Vol. 136 (9), pp. 3993-4003. - Publication Year :
- 1995
-
Abstract
- In this study the luteotropic activity of mouse placental lactogen I (mPL-I) at midpregnancy was assessed using in vivo and in vitro methodologies. Ovaries from 10-day pregnant mice were enzymatically dispersed and plated on fibronectin-coated wells in serum-free medium. The percentage of ovarian cells that stained for the presence of 3 beta-hydroxysteroid dehydrogenase activity was 24.4 +/- 2.7% at the time of plating and remained constant (26.1 +/- 5.0%) after a 20-h attachment period. Two types of 3 beta-hydroxysteroid dehydrogenase-staining cells, with distinct differences in size and morphology, were present in the culture. Large luteal cells (26-45 microns) were characterized by a small round nucleus and spherical shape with abundant cytoplasm. In contrast, small luteal cells (< 20 microns) were stellate, with little cytoplasm and a large oval nucleus. Basal progesterone secretion was maintained without a change in cellular DNA content and cell number for 168 h of culture. Treatment of ovarian cells with mPL-I (0.05-10 micrograms/ml) caused a dose-dependent increase in the progesterone concentration in the medium. The magnitude and time course of mPL-I-stimulated progesterone accumulation in culture were dependent on the time after plating that mPL-I treatment was initiated. The effects of mPL-II and mouse PRL (mPRL) on progesterone production were similar to those of mPL-I. The ability of sera from 10-, 14-, and 17-day pregnant mice to maintain progesterone production in bromocryptine-treated hysterectomized mice was also examined. Mice were hysterectomized on day 9 of pregnancy, and serum progesterone, mPL-I, mPL-II, and mPRL concentrations were measured 72 h later. Twice daily injections of 0.5 ml day 10 pregnancy serum maintained the circulating progesterone concentration at values not different from those present at the time of hysterectomy. In contrast, serum progesterone concentrations were not maintained in mice treated with serum of 14- or 17-day pregnant mice or with saline. Depletion of mPL-I from day 10 pregnancy serum by affinity chromatography on an anti-mPL-I column removed all luteotropic activity, as determined by the inability of this modified serum to maintain the serum progesterone concentration in bromocryptine-treated hysterectomized mice. A similar pool of day 10 pregnancy serum chromatographed on a nonspecific IgG control column did maintain progesterone production, but at somewhat lower concentrations than those present at the time of surgery. These studies offer direct evidence that mPL-I and mPL-II are luteotropic and support progesterone production at midpregnancy in the mouse.
- Subjects :
- 3-Hydroxysteroid Dehydrogenases analysis
Animals
Bromocriptine pharmacology
Cells, Cultured
Chromatography, Affinity
Corpus Luteum cytology
Corpus Luteum drug effects
DNA analysis
DNA genetics
Dose-Response Relationship, Drug
Female
Hysterectomy
Mice
Ovary chemistry
Ovary cytology
Ovary enzymology
Placental Lactogen metabolism
Placental Lactogen pharmacology
Pregnancy
Pregnancy, Animal blood
Pregnancy, Animal metabolism
Progesterone blood
Progesterone metabolism
Prolactin metabolism
Prolactin pharmacology
Prolactin physiology
Radioimmunoassay
Time Factors
Corpus Luteum physiology
Placental Lactogen physiology
Pregnancy, Animal physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0013-7227
- Volume :
- 136
- Issue :
- 9
- Database :
- MEDLINE
- Journal :
- Endocrinology
- Publication Type :
- Academic Journal
- Accession number :
- 7649108
- Full Text :
- https://doi.org/10.1210/endo.136.9.7649108