Lack of Effect of Insulin or Insulin-Like Growth Factor I on the Steroid Sulfatase Activity of Human Placental Cytotrophoblasts

Je, Nestler

doi:10.1055/s-2007-1009207

Cited by 3 publications

(1 citation statement)

References 5 publications

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“…This was clearly shown by both methods, i.e., immunostaining and enzyme assays (Table 1 and Fig. 1), and is in agreement with earlier reports (Dibbelt et al, 1989(Dibbelt et al, , 1994Nestler, 1989). In contrast, Salido et al (1990) could not demonstrate STS expression in cytotrophoblasts by immunostaining and in situ hybridization.…”

Section: Discussionsupporting

confidence: 92%

Differential increase of steroid sulfatase activity in XX and XY trophoblast cells from human term placenta with syncytia formation in vitro

Ugele¹,

Regemann²

2000

Cytogenet Genome Res

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Steroid sulfatase (STS, EC 3.1.6.2) catalyzes the hydrolysis of the sulfate ester bonds of a variety of sulfated steroids, such as cholesterol, dehydroepiandrosterone, and estrone sulfate, a reaction influencing fertility and breast cancer in mammals. The activity of the enzyme is substantially elevated in placental syncytiotrophoblasts and is lower in other somatic cells. The polypeptide sequence of the enzyme is encoded by a gene located on the distal short arm of the human X chromosome. Prior studies have shown that the STS gene escapes X-chromosome inactivation. We studied the expression of the STS gene in primary cultures of cytotrophoblasts from human term placentae and compared it with the expression of autosomally encoded placental alkaline phosphatase (PALP) and X-linked glucose-6-phosphate dehydrogenase (G6PD). During 90 h in culture, the mononucleated cytotrophoblast cells did not proliferate, but differentiated into multinucleated, syncytiotrophoblast-like cells. STS activity in freshly isolated cytotrophoblasts was low (about 17%), compared to placental tis- sue, and about 1.7-fold higher in female than in male cells. During cultivation, STS activity increased 2- to 3-fold in female, but not in male, cells. PALP activity was very low in freshly isolated cytotrophoblasts (about 5% of placental tissue), and no significant difference between female and male cells was detectable. Within 90 h in culture, PALP activity increased in all preparations about 2- to 4-fold. G6PD activity in freshly isolated cytotrophoblasts showed great variation among preparations, and no significant difference between female and male cells was detectable. In both male and female cells the activity declined to about 50% of initial activity during cultivation. We conclude that human cytotrophoblasts in primary culture show a sex-specific regulation of STS activity, perhaps as a unique feature of the STS gene. The cytotrophoblast system may offer a new possibility to study the regulation of STS gene expression.

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Section: Discussionsupporting

confidence: 92%

Differential increase of steroid sulfatase activity in XX and XY trophoblast cells from human term placenta with syncytia formation in vitro

Ugele¹,

Regemann²

2000

Cytogenet Genome Res

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Placental metabolism and its regulation in health and diabetes

Desoyé

Shafrir

1994

Molecular Aspects of Medicine

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Suppression of Serum Dehydroepiandrosterone Sulfate Levels by Insulin: An Evaluation of Possible Mechanisms *

Nestler

Usiskin

Barlascini

et al. 1989

The Journal of Clinical Endocrinology & Metabolism

124

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We previously demonstrated a progressive decline in serum dehydroepiandrosterone sulfate (DHEA-S) levels in women during a hyperinsulinemic-euglycemic clamp. To determine whether this fall in serum DHEA-S levels might have been due to insulin-stimulated 1) hydrolysis of DHEA-S to dehydroepiandrosterone (DHEA), 2) conversion of DHEA-S/DHEA to androstenedione, and/or 3) urinary excretion of these steroids, 10 additional men were studied by the hyperinsulinemic-euglycemic clamp technique. Each man received a 0.1 U/kg (0.72 nmol/kg) insulin bolus dose, followed by a 10 mU/kg.min (72 pmol/kg.min) insulin infusion for 4 h. An average insulin level of 12,390 +/- 259 (+/- SE) pmol/L (1,726.8 +/- 36 microU/mL) was achieved; serum glucose was maintained at 5.0 +/- 0.1 mmol/L (90.5 +/- 2.3 mg/dL). During the hyperinsulinemia, serum DHEA-S levels fell progressively and were significantly lower than baseline at 4 and 6 h of study (85.5 +/- 5.9% and 79.1 +/- 3.2% of baseline values, respectively; P less than 0.05). Serum DHEA levels fell concurrently and were significantly lower than baseline at 2, 4, and 6 h of study (66.2 +/- 12.3%, 61.6 +/- 11.2%, and 52.9 +/- 10.2% of baseline values, respectively; P less than 0.05). The percent fall in serum DHEA levels correlated positively with the percent fall in serum DHEA-S levels (r = 0.44; P less than 0.02). Serum androstenedione levels also fell progressively during hyperinsulinemia and were significantly lower than baseline at 2, 4, and 6 h of study (71.5 +/- 4.1%, 71.0 +/- 7.2%, and 48.1 +/- 3.3% of baseline values, respectively; P less than 0.05). No change in serum DHEA-S, DHEA, or androstenedione levels occurred in paired control studies, during which 0.45% saline was infused at rates matched exactly to the rates of the dextrose and insulin infusions during the hyperinsulinemic clamp studies. Despite decreasing serum DHEA-S and DHEA levels during hyperinsulinemia, urinary DHEA-S and DHEA glucuronide excretions were increased by 50% (P less than 0.05) and 86% (P = 0.05), respectively, compared to urinary excretion of these steroids during control studies. In contrast, urinary excretion of unconjugated DHEA was unchanged. Quantitatively, however, increased urinary excretion of conjugated DHEA during hyperinsulinemia accounted for only about 5% of the concomitant fall in serum DHEA-S concentrations.(ABSTRACT TRUNCATED AT 400 WORDS)

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Lack of Effect of Insulin or Insulin-Like Growth Factor I on the Steroid Sulfatase Activity of Human Placental Cytotrophoblasts

Cited by 3 publications

References 5 publications

Differential increase of steroid sulfatase activity in XX and XY trophoblast cells from human term placenta with syncytia formation in vitro

Differential increase of steroid sulfatase activity in XX and XY trophoblast cells from human term placenta with syncytia formation in vitro

Placental metabolism and its regulation in health and diabetes

Suppression of Serum Dehydroepiandrosterone Sulfate Levels by Insulin: An Evaluation of Possible Mechanisms *

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