Sex Differences in Reactivity of the Sympathoadrenal System in Rat Ontogenesis

• Published in: Journal of evolutionary biochemistry and physiology 2003-07, Vol.39 (4), p.468-473
• Main Authors: Mikhailenko, V. A., Vataeva, L. A., Makukhina, G. V.
• Format: Article
• Language: English
• Subjects: Males
• ISSN: 0022-0930; 1608-3202
• DOI: 10.1023/B:JOEY.0000010244.73326.a2

Sex differences in reactivity of the sympathoadrenal system were studied in male and female Wistar rats of three age groups (22-day-old, 31-day-old, and adult). An essential increase of catecholamine excretion level in males between the 22nd and 31st day after the birth has been noted both after stress (immobilization water-immersion action) and after injection of α ^sub 2^-adrenoblockator yohimbine. In females the response to stress and injection of yohimbine practically did not change at this age stage. The sex dimorphism revealed as a higher level of adrenaline excretion in the 22-day-old females, as compared with males, was characterized in older groups by a higher level of its excretion in males. It might be suggested that sex dimorphism in non-reproductive types of behavior can depend on two factors: on differences in the maturity rate between females and males and on direct or mediated effects of sex hormones on physiological processes and related behavioral reactions.[PUBLICATION ABSTRACT]