5α-Reductase activity in human placenta

L. Milewich, N. F. Gant, B. E. Schwarz, G. T. Chen, P. C. MacDonald

Research output: Contribution to journalArticle

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Abstract

The concentration of 5α-pregnane-3,20-dione in peripheral blood of pregnant women is higher than that found in blood obtained from nonpregnant women throughout the luteal phase of the ovulatory cycle. The in vitro synthesis of 5α-reduced pregnanes from [ 3H]progesterone by placental tissue was investigated using tissue minces and homogenates in the presence of added nicotinamide-adenine dinucleotide phosphate. The metabolites, [ 3H]5α-pregnane-3,20-dione and [ 3H]3β-hydroxy-5α-pregnan-20-one, were isolated and characterized employing a combination of chromatographic techniques, derivative formation, and crystallization with authentic [ 14C]5α-pregnane-3,20-dione and [ 14C]3β-hydroxy-5α-pregnan-20-one to constant 3H: 14C ratios. In short-term incubations with placenta homogenates, the apparent pH optimum for the synthesis of 5α-pregnane-3,20-dione was 8.8. There was no evidence for the formation of 5β-reduced pregnanes from [ 3H]progesterone by placental tissue. The in vitro metabolism of [ 3H]progesterone by minces of five term placentas, during 1 hour incubations at pH 7.4, was studied. The rate of formation of 5α-pregnane-3,20-dione varied from 109 to 197 pmoles/gm placental tissue/hr.

Original languageEnglish (US)
Pages (from-to)611-617
Number of pages7
JournalAmerican Journal of Obstetrics and Gynecology
Volume133
Issue number6
StatePublished - 1979

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Pregnanes
Human Activities
Placenta
Oxidoreductases
Progesterone
Luteal Phase
Crystallization
NADP
Pregnant Women

ASJC Scopus subject areas

  • Medicine(all)
  • Obstetrics and Gynecology

Cite this

Milewich, L., Gant, N. F., Schwarz, B. E., Chen, G. T., & MacDonald, P. C. (1979). 5α-Reductase activity in human placenta. American Journal of Obstetrics and Gynecology, 133(6), 611-617.

5α-Reductase activity in human placenta. / Milewich, L.; Gant, N. F.; Schwarz, B. E.; Chen, G. T.; MacDonald, P. C.

In: American Journal of Obstetrics and Gynecology, Vol. 133, No. 6, 1979, p. 611-617.

Research output: Contribution to journalArticle

Milewich, L, Gant, NF, Schwarz, BE, Chen, GT & MacDonald, PC 1979, '5α-Reductase activity in human placenta', American Journal of Obstetrics and Gynecology, vol. 133, no. 6, pp. 611-617.
Milewich L, Gant NF, Schwarz BE, Chen GT, MacDonald PC. 5α-Reductase activity in human placenta. American Journal of Obstetrics and Gynecology. 1979;133(6):611-617.
Milewich, L. ; Gant, N. F. ; Schwarz, B. E. ; Chen, G. T. ; MacDonald, P. C. / 5α-Reductase activity in human placenta. In: American Journal of Obstetrics and Gynecology. 1979 ; Vol. 133, No. 6. pp. 611-617.
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