Endocrine correlates of partner preference behavior in rams

• Published in: Biology of reproduction Vol. 55; no. 1; pp. 120 - 126
• Main Authors: Resko, J.A. (Oregon Health Sciences University, Portland, OR.), Perkins, A, Roselli, C.E, Fitzgerald, J.A, Choate, J.V.A, Stormshak, F
• Format: Journal Article
• Language: English
• Published: Madison, WI Society for the Study of Reproduction 01.07.1996
• Subjects: 17-alpha-Hydroxyprogesterone; 17-alpha-Hydroxyprogesterone - metabolism; ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; ANDROSTENEDIONA; ANDROSTENEDIONE; Androstenedione - blood; Animals; Aromatase; Aromatase - metabolism; Behavioral psychophysiology; BELIER; Biological and medical sciences; biosynthesis; blood; blood serum; brain; Brain - enzymology; CEREBRO; COMPORTAMIENTO SEXUAL; COMPORTEMENT SEXUEL; Dihydrotestosterone; Dihydrotestosterone - blood; ENCEPHALE; enzyme activity; enzymology; estradiol; Estradiol - blood; ESTROGENOS; estrone; Estrone - blood; Female; Fundamental and applied biological sciences. Psychology; Gonadal Steroid Hormones; Gonadal Steroid Hormones - blood; homosexuality; Homosexuality, Male; HORMONAS; HORMONE; hormone secretion; Hormones and behavior; Male; metabolism; METABOLISME DES STEROIDES; METABOLISMO DE ESTEROIDES; MORUECO; OESTROGENE; OXIDORREDUCTASAS; OXYDOREDUCTASE; oxygenases; physiology; Preoptic Area; Preoptic Area - enzymology; PROGESTERONA; PROGESTERONE; Progesterone - metabolism; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; rams; SECRECION; SECRETION; SERUM SANGUIN; Sexual Behavior, Animal; Sexual Behavior, Animal - physiology; Sheep; steroidogenesis; SUERO SANGUINEO; testes; TESTICULE; TESTICULOS; Testis; Testis - metabolism; TESTOSTERONAS; TESTOSTERONE; Testosterone - biosynthesis; Testosterone - blood; Androgen; Enzyme; Estrogen; Central nervous system; Sexual behavior; 17β-Estradiol; Male; Mate selection; Estrogen synthase; Testicle; Male genital system; Breeding behavior; Ovarian hormone; Testosterone; Vertebrata; Mammalia; Sheep; Steroidogenesis; Artiodactyla; Testicular hormone; Hormonal investigation; Sex steroid hormone; Ungulata; Brain (vertebrata)
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod55.1.120

We studied a unique group of rams that would not mate with estrous ewes during extensive testing for sexual behavior. The same rams courted males in preference to females in 30-min sexual preference tests and were classified as male-oriented (n = 6). We compared the following endocrine profiles: systemic steroid concentrations, the capacity of the testes to biosynthesize 17alpha-hydroxyprogesterone and testosterone from 3H-progesterone in vitro, and the levels of brain aromatase activity (AA) in male-oriented rams vs. rams that were proven breeders and designated as female-oriented (n = 7). After the last behavioral test, sera were collected, and males in each experimental group were killed. Brains and testes were obtained for subsequent determinations of AA and measurements of steroidogenic enzyme activity. All dissections and subsequent assays were performed without knowledge of experimental group assignments. Serum concentration of testosterone (T), dihydrotestosterone (DHT), androstenedione, estrone (E1), and estradiol-17beta (E2) were determined by RIA. AA was quantified by a 3H2O assay validated for neural tissue of the ram. We studied frontal, parietal and cingulate cortex, cerebellum, hippocampus, olfactory bulb, septum, amygdala, infundibulum-median eminence, and preoptic area (POA). Serum T, E1, and E2 concentrations of female-oriented subjects were significantly higher (p 0.05) than those in male-oriented subjects (SEM: 1559 +/- 228, 46 +/- 2, and 15 +/- 3 pg/ml vs. 874 +/- 196, 40 +/- 2, and 8 +/- 1 pg/ml serum, respectively). DHT and androstenedione concentrations in the systemic circulation did not differ between groups