Effect of neonatal β-endorphin imprinting on sexual behavior and brain serotonin level in adult rats

G. Csaba, Barbara Knippel, Cs Karabélyos, Ágnes Inczefi-Gonda, Monika Hantos, L. Tóthfalusi, Kornélia Tekes

Research output: Contribution to journalArticle

24 Citations (Scopus)


A single dose (3 μg) β-endorphin was administered to newborn female and male rats (hormonal imprinting). In adult age (at 5 months) sexual behavior, steroid hormone binding capacity and brain serotonin content was studied. Females' sexual activity (lordosis quotient) significantly decreased and more animals protested against mounting (ratio of kicking and crying 21/24 vs. 8/24; p < 0.001). Males' sexual activity did not change, however more males were aggressive (4/10 vs. 1/10). Uterine estrogen receptor density significantly increased and affinity decreased. There was no change in the binding capacity of thymic glucocorticoid receptors. In the brain, five regions were studied for serotonin content. There was a gender difference in serotonin level and the intragroup differences were also high. In the endorphin treated males the serotonin level was significantly lower than in the controls. In the endorphin treated females the intragroup scattering has been significantly reduced. Nociceptin content of the cerebrospinal fluid was not changed. The experiments call attention to the possibility of adjustment of sexual and behavioral sphere by the individually different endorphin surge during labor.

Original languageEnglish
Pages (from-to)103-114
Number of pages12
JournalLife Sciences
Issue number1
Publication statusPublished - May 23 2003


  • Aggression
  • Brain
  • Gender difference
  • Hormonal imprinting
  • Newborn
  • Nociceptin
  • Serotonin
  • Sexual behavior
  • Steroid receptors
  • β-endorphin

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

Fingerprint Dive into the research topics of 'Effect of neonatal β-endorphin imprinting on sexual behavior and brain serotonin level in adult rats'. Together they form a unique fingerprint.

  • Cite this