Infantile 4-tert-octylphenol exposure transiently inhibits rat ovarian steroidogenesis and steroidogenic acute regulatory protein (StAR) expression

Journal Article · Mon Aug 22 04:00:00 EDT 2005 · Toxicology and Applied Pharmacology

DOI:https://doi.org/10.1016/j.taap.2004.12.001· OSTI ID:20721870

Myllymaeki, S A ^[1]; Karjalainen, M ^[2]; Haavisto, T E ^[3]; Toppari, J ^[4]; Paranko, J ^[5]

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1. Department of Biology, Laboratory of Animal Physiology, 20014 University of Turku (Finland) and Department of Physiology, University of Turku, 20520 Turku (Finland)
2. Faculty of Veterinary Medicine, 00014 University of Helsinki (Finland)
3. Department of Biology, Laboratory of Animal Physiology, 20014 University of Turku (Finland)
4. Department of Physiology, University of Turku, 20520 Turku (Finland)
5. Department of Anatomy, University of Turku, 20520 Turku (Finland)

Phenolic compounds, such as 4-tert-octylphenol (OP), have been shown to interfere with rat ovarian steroidogenesis. However, little is known about steroidogenic effects of infantile OP exposure on immature ovary. The aim of the present study was to investigate the effects of infantile OP exposure on plasma FSH, LH, estradiol, and progesterone levels in 14-day-old female rats. The effect on ovarian steroidogenic acute regulatory protein (StAR) and FSH receptor (FSHr) expression was analyzed by Western blotting. Ex vivo analysis was carried out for follicular estradiol, progesterone, testosterone, and cAMP production. Sprague-Dawley rats were given OP (0, 10, 50, or 100 mg/kg) subcutaneously on postnatal days 6, 8, 10, and 12. On postnatal day 14, plasma FSH was decreased and progesterone increased significantly at a dose of 100 mg OP/kg. In addition, the highest OP dose advanced the time of vaginal opening in puberty. OP had no effect on infantile LH and estradiol levels or ovarian FSHr content. Ovarian StAR protein content and ex vivo hormone and cAMP production were decreased at all OP doses compared to controls. However, hormone levels recovered independent on FSH and even increased above the control level during a prolonged culture. On postnatal day 35, no statistically significant differences were seen between control and OP-exposed animals in plasma FSH, LH, estradiol, and progesterone levels, or in ovarian StAR protein content. The results indicate that the effect of OP on the infantile ovary is reversible, while more permanent effects in the hypothalamus and pituitary, as described earlier, are involved in the reduction of circulating FSH levels and premature vaginal opening.

• OSTI ID: 20721870
• Journal Information: Toxicology and Applied Pharmacology, Journal Name: Toxicology and Applied Pharmacology Journal Issue: 1 Vol. 207; ISSN TXAPA9; ISSN 0041-008X
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
AMP
ESTRADIOL
FSH
HYPOTHALAMUS
OVARIES
PROGESTERONE
RATS
RECEPTORS
TESTOSTERONE