Induction of sexual behavior in female rats by the 17beta-aminoestrogens prolame, butolame and pentolame.

17beta-aminoestrogens (AEs) decrease luteinizing hormone levels, increase uterine weight, activate transcription through ERalpha and ERbeta receptors and induce progesterone receptor expression in the anterior pituitary. This work evaluates the influence of single and multiple administration of a homologous series of the AEs: prolame, butolame and pentolame on rat female sexual behavior to explore their capability of inducing lordosis by themselves. In a reversed cycle the animals received one or three subcutaneous (s.c.) injections at 8:00 hr of: 7.5 microg E2/day (approximately 30 microg/kg), or 10 microg BE/day (approximately 40 microg/kg), or 1 mg/day prolame, butolame, pentolame (approximately 4000 microg/kg), or 300 microL/day of corn oil (approximately 1.2 ml/kg). Twenty-four hr following treatment, progesterone (P; 1 mg/0.1 ml of corn oil/rat) was administered; and 5 to 7 hr later, rats were tested for sexual receptivity and the lordosis quotient (LQ) was estimated (number of lordosis displays/number of mounts x 100). Single administration by themselves did not facilitate lordosis, 24 hr after the second injection, AEs-LQs values were: 24, 30, 21, E2 = 13 and EB = 11. administrations of three AEs increased LQs to: 48, 50, 45 E2 = 33 and EB = 57. The sequential P administration facilitated lordosis; after one injection: LQs 50-90 (p<0.01), meanwhile E2 and BE inducing LQs of 43 and 81 respectively. After the second and third injections and P administration the AEs LQs were 92-100 (p<0.01) similarly to E2 (95; p<0.01) and BE (96; p<0.01). The facilitation of sexual behavior by AEs was time and dose-dependent.