Lordotic behavior in male rats: Genetic and hormonal regulation of sexual differentiation

• Published in: Hormones and behavior Vol. 20; no. 1; pp. 73 - 82
• Main Authors: Whalen, Richard E, Gladue, Brian A, Olsen, K.L
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.03.1986; Elsevier
• Subjects: Androstatrienes - pharmacology; Animals; Biological and medical sciences; Estradiol - pharmacology; Female; Fundamental and applied biological sciences. Psychology; Gonadal Steroid Hormones - pharmacology; Male; Mammalian male genital system; Morphology. Physiology; Posture; Pregnancy; Progesterone - pharmacology; Rats; Rats, Inbred Strains; Sex Differentiation - drug effects; Sexual Behavior, Animal - drug effects; Sexual Behavior, Animal - physiology; Species Specificity; Vertebrates: reproduction; Vertebrata; Sexual behavior disorder; Mammalia; Rat; Rodentia; Hormonal regulation; Genetics; Lordosis; Male; Sexual differentiation
• ISSN: 0018-506X; 1095-6867
• DOI: 10.1016/0018-506X(86)90030-9

The male offspring of Long-Evans rats treated with the aromatization inhibitor ATD (1,4,6-androstatriene-3,17-dione) during pregnancy show high levels of lordotic behavior when treated with estrogen and progesterone in adulthood. The male offspring of Sprague-Dawley dams treated in the same way show only a slight facilitation of lordotic potential. These strain differences could reflect strain differences in gestation length and therefore differences in the timing of the sensitive period of sexual differentiation; they could reflect differences in the sensitivity to the defeminizing actions of gonadal hormones; or they could reflect differences in the sensitivity to ATD treatment. We therefore directly compared the effects of prenatal and early postnatal treatment with ATD on the potential of male Long-Evans and Sprague-Dawley rats to show lordosis when given estrogen and progesterone in adulthood. In both strains ATD treatment facilitated adult lordotic behavior. Treatment appeared to have a greater effect in the Long-Evans strain. However, control Long-Evans males were substantially more responsive to hormone treatment in adulthood than were Sprague-Dawley males. In the Long-Evans strain short-term ATD treatment (Days 20–23 of pregnancy) was as effective as long-term treatment (Days 10–23). In the Sprague-Dawley strain, ATD treatment was most effective when given prenatally and postnatally. Strain differences in hormonal sensitivity best account for the present findings.