EFFECTS OF ANTIANDROGEN ON SEXUAL BEHAVIOR, ORGAN WEIGHT AND HORMONE LEVELS OF MALE RATS

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 524-553-Male Reproductive Endocrinology
Bench to Bedside
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-551
Manami Kamishima*1, Hanae Uemura1, Yasuyuki Horii2, Gen Watanabe2, Kazuyoshi Taya2, Toshio Harigaya3, Hidetaka Takigami4, Go Suzuki4, Yasuhiko Kondo5 and Maiko Kawaguchi3
1Meiji University, Kawasaki, Japan, 2Tokyo University of Agriculture and Technology, 3Meiji University, Kawasaki Kanagawa, Japan, 4National Institute for Environmental Studies, 5Teikyo University of Science
It is known that administration with flutamide, a non-steroidal anti-androgen, does not prevent copulatory behavior of sexually experienced male rats despite the suppression of peripheral androgen-sensitive tissues. However, there is still not enough data about the effects of flutamide during development from newborn to juvenile. In this study, we investigated the effects of long-term exposure to flutamide during development on sexual behavior, sexual preference (access to opposite-sex partner), organ weight (including external /internal genital organs) and hormone levels in male rats.

Pregnant Wistar-Imamichi rats were obtained from the Institute for Animal Reproduction, Ibaraki, Japan. All the rats were maintained under a 12:12 light-dark cycle and food and water were available ad libitum throughout the experiment. From postnatal day 0 (PD0) to PD27, male pups were administered orally with either 5 mg / kg / day flutamide or sesame oil (control). Male offspring of both groups were tested for sexual behavior and preference test 3 times (between 15 and 18 weeks old). At 19 weeks old, all rats were sacrificed to collect blood samples and dissect organ specimens given below for analyzing peripheral effects of flutamide: coagulating gland, seminal vesicle, prostate gland, penis, testes and epididymis. Penile length was measured and plasma levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone were determined.

Although all rats in both flutamide and control groups showed mount activity in sexual behavior test, flutamide treatments significantly decreased number of intromissions and ejaculations, and increased latencies of mount, intromission and ejaculation, compared to those of the controls. In contrast, no significant difference was seen in sexual preference tests between the two groups. In the flutamide group, penile lengths and weights were decreased compared to those of the controls, while no significant difference in other organ weights per body weights and in the hormonal levels were found between the groups.

In conclusion, Long-term exposure to flutamide during development suppressed sexual behavior and penile growth but did not affect sexual preference and hormone levels in male rats. Although the suppression of sexual behavior may be caused by hypoplasia of penis, it is still possible that such exposure affects brain function because of increased latencies of sexual behaviors.

Nothing to Disclose: MK, HU, YH, GW, KT, TH, HT, GS, YK, MK

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: This work was supported by Grants-in-Aid for Young Scientists(A) (no. 23681011).