[Effect of sexual pheromones, and sexual and paternal behaviors on the plasma level of testosteron in male wistar rat]

ABSTRACT

Pheromones play a major role in the sexual and social behavior of animals. The main sources of pheromones are urine and paracrine secretions. Pheromones can affect the mammals reproductive physiology. The vomeronasal organ [VNO] is located in the base of nasal cavity and VNO has some effects on amygdal; stimulating the amygdal hence could affectthe mammal's sexual behavior. Through the neuroendocrine system, testosterone is a safe parameter to measure and compare the effects on the sexual behavior. With regard to the neuroendocrine system, testosterone is a safe parameter for measuring the effects of pheromones on sexual behaviors. In this research, we have investigated the of pheromone interaction on sexual behaviors such as intercourse, mating and being near a pregnant female, also paternal behavior after children's birth, have been investigated. The effects of sexual pheromones were determined with a special cage without any sensory stimulation interference, such as visual, auditory, tactile senses [3.58 +/- 0.38 ng/mL]. Proximity between a female and a male rat increased plasma levels of testosterone rapidly [10.59 +/- 2.25 ng/mL, P<0.01]. Mating caused a decrease in testosterone levels comparing to premate groups [4.32 +/- 0.95 ng/mL, P<0.05]. During pregnancy, the testosterone levels increased up to the second week [6.11 +/- 1.58 ng/mL, P<0.017] then decreased rapidly[1.65 +/- 0.37 ng/mL, P<0.017]. After birth of children, the father rat testosterone levels decreased gradually [0.36 +/- 0.14 ng/mL, P<0.017]. But the presence of the father rat's near the strange child rat, the plasma levels of testosterone to increase significantly compared to the increase in mating groups[8.46 +/- 1.26 ng/mL, P<0.017]. These findings suggest that female sexual pheromones and different fatherhood and sexual behaviors, directly affect plasma levels of testosterone and can subsequently affect mating rats' reproductive activities