Progesterone Production Rates During the Third Trimester of Pregnancy in Normal Women, Diabetic Women, and Women with Abnormal Glucose Tolerance1

Lin, Ta-Jung; Lin, Su-Chin; Erlenmeyer, F.; Kline, Irene T.; Underwood, Richard H.; Billiar, Reinhart B.; Little, Brian

doi:10.1210/jcem-34-2-287

Cited by 59 publications

(5 citation statements)

References 2 publications

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“…Our values for the MCR of Prog were the same in men as in women in both phases of the menstrual cycle and were nearly identical to those reported by Little et al (34) in males and ovariectomized females and by Lin et al (35) in normal pregnant and diabetic pregnant women. The high MCR of Prog indicates high hepatic extraction, suggesting that under physiological conditions, most Prog is free and albumin bound, and only a small fraction is bound to transcortin, as is true for aldosterone and DOC (14).…”

Section: Discussionsupporting

confidence: 90%

Physiological Concentrations of Growth Hormone Exert Insulin-Like and Insulin Antagonistic Effects on Both Hepatic and Extrahepatic Tissues in Man*

Antonipillai

Moghissi

Hawks

et al. 1983

The Journal of Clinical Endocrinology & Metabolism

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The in vivo conversion of progesterone (Prog) to deoxycorticosterone (DOC) was determined in the circulation of men and women. Labeled Prog was given by constant infusion under steady state conditions, and plasma Prog and DOC were isolated by column, paper, and high pressure liquid chromatographies. Blood production rates (PR) were calculated from the product of the morning plasma concentrations measured by RIA and the MCR. The DOC MCR was determined using data from our previous study. In men, the Prog and DOC levels were 9.8 ± 2.3 (±SE) and 7.8 ± 0.4 ng/dl, respectively. The Prog, MCR averaging the 105 and 120 min samples, was 1968 ± 132 liters/ day, and the PR was 194 ± 46 /xg. The conversion ratio (CR) was 1.3 ± 0.2%, which, taken together with plasma Prog and DOC levels, indicates that less than 2% of plasma DOC was from Prog in blood. Similar data were found in women in the follicular phase. Plasma levels of Prog and DOC were 8.3 ± 1.0 and 6.4 ± 0.6 ng/dl, respectively. The MCR was 1955 liters/day, the Prog PR was 162 ± 13 jug/day, and the DOC PR was 84 ± 8 /ig/day. Since the CR was 1.4%, again, less than 2% of DOC was from circulating Prog. However, in the midluteal phase, plasma Prog rose to 1073 ± 101 ng/dl, and DOC increased to 15.6 ±1.1 ng/dl (P < 0.001). The Prog MCR and PR were 2246 ± 302 liters/day and 24.6 ± 2.3 mg/day, respectively, with a DOC PR increasing to 204 ± 14 jitg. Despite the finding that the CR remained at 1.2 ± 0.2%, the calculations indicate that 83% of the DOC in the luteal phase is from Prog.These studies indicate that Prog can be 21-hydroxylated to DOC by peripheral tissue, but the conversion seems to be unaffected by sex or the precursor level. In men and in women in the follicular phase, DOC in plasma is from direct adrenal secretion. However, in the normal luteal phase, most plasma DOC (more than 75%) is derived from Prog secreted by the corpus luteum. (J Clin Endocrinol Metab 56: 93, 1983)

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Section: Discussionsupporting

confidence: 90%

Physiological Concentrations of Growth Hormone Exert Insulin-Like and Insulin Antagonistic Effects on Both Hepatic and Extrahepatic Tissues in Man*

Antonipillai

Moghissi

Hawks

et al. 1983

The Journal of Clinical Endocrinology & Metabolism

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“…The mechanisms of syncytial trophoblast formation have been debated in the literature. Elegant work has been reported which strongly supports the notion that of the two types of trophoblasts, only the cytotrophoblasts are mitotically active, and they form the syncytium by fusion (32)(33)(34). Ultrastructural studies on intact placenta have shown syncytia with intracytoplasmic remnants of desmosomes and cell membranes, suggestive of a recent fusion event (2,3).…”

Section: Discussionmentioning

confidence: 92%

Purification, Characterization, andin vitroDifferentiation of Cytotrophoblasts from Human Term Placentae*

et al. 1986

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Highly purified functional cytotrophoblasts have been prepared from human term placentae by adding a Percoll gradient centrifugation step to a standard trypsin-DNase dispersion method. The isolated mononuclear trophoblasts averaged 10 microns in diameter, with occasional cells measuring up to 20-30 microns. Viability was greater than 90%. Transmission electron microscopy revealed that the cells had fine structural features typical of trophoblasts. In contrast to syncytial trophoblasts of intact term placentae, these cells did not stain for hCG, human placental lactogen, pregnancy-specific beta 1-glycoprotein or low mol wt cytokeratins by immunoperoxidase methods. Endothelial cells, fibroblasts, or macrophages did not contaminate the purified cytotrophoblasts, as evidenced by the lack of immunoperoxidase staining with antibodies against vimentin or alpha 1-antichymotrypsin. The cells produced progesterone (1 ng/10(6) cells . 4 h), and progesterone synthesis was stimulated up to 8-fold in the presence of 25-hydroxycholesterol (20 micrograms/ml). They also produced estrogens (1360 pg/10(6) cells . 4 h) when supplied with androstenedione (1 ng/ml) as a precursor. When placed in culture, the cytotrophoblasts consistently formed aggregates, which subsequently transformed into syncytia within 24-48 h after plating. Time lapse cinematography revealed that this process occurred by cell fusion. The presumptive syncytial groups were proven to be true syncytia by microinjection of fluorescently labeled alpha-actinin, which diffused completely throughout the syncytial cytoplasm within 30 min. Immunoperoxidase staining of cultured trophoblasts between 3.5 and 72 h after plating revealed a progressive increase in cytoplasmic pregnancy-specific beta 1-glycoprotein, hCG, and human placental lactogen concomitant with increasing numbers of aggregates and syncytia. At all time points examined, occasional single cells positive for these markers were identified. RIA of the spent culture media for hCG revealed a significant increase in secreted hCG, paralleling the increase in hCG-positive cells and syncytia identified by immunoperoxidase methods. We conclude that human cytotrophoblasts differentiate in culture and fuse to form functional syncytiotrophoblasts.

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“…During late human pregnancy, 250 mg or more of progesterone enter the maternal circulation each day (20,21). Thus, even a small fractional conversion of maternal plasma progesterone to DOC could account for considerable DOC production compared to that normally secreted by the adrenal cortex.…”

Section: Introductionmentioning

confidence: 99%

Conversion of plasma progesterone to deoxycorticosterone in men, nonpregnant and pregnant women, and adrenalectomized subjects.

Winkel¹,

Milewich²,

Parker³

et al. 1980

J. Clin. Invest.

105

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Progesterone Production Rates During the Third Trimester of Pregnancy in Normal Women, Diabetic Women, and Women with Abnormal Glucose Tolerance1

Cited by 59 publications

References 2 publications

Physiological Concentrations of Growth Hormone Exert Insulin-Like and Insulin Antagonistic Effects on Both Hepatic and Extrahepatic Tissues in Man*

Physiological Concentrations of Growth Hormone Exert Insulin-Like and Insulin Antagonistic Effects on Both Hepatic and Extrahepatic Tissues in Man*

Purification, Characterization, andin vitroDifferentiation of Cytotrophoblasts from Human Term Placentae*

Conversion of plasma progesterone to deoxycorticosterone in men, nonpregnant and pregnant women, and adrenalectomized subjects.

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