Relationship of serum testosterone concentrations to mate preferences in rams

Charles Roselli, Fred Stormshak, John N. Stellflug, John A. Resko

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

This study examined systemic testosterone concentrations in rams that were classified according to their sexual behavior and partner preference as either female-oriented (FOR), male-oriented (MOR), or asexual (NOR). For this purpose, we measured testosterone concentrations under three separate conditions: in conscious rams during the nonbreeding season (June) and breeding season (November), and in anesthetized rams during the breeding season. Basal testosterone concentrations in conscious rams were not different among the three groups (P > 0.05) in either season. However, when rams were anesthetized, mean systemic concentrations of testosterone in FORs (mean ± SEM, 13.9 ± 7.4 ng/ml serum) were greater (P <0.05) than in NORs (0.9 ± 0.1 ng/ml), but not in MORs (2.2 ± 6.2 ng/ml), whereas testosterone concentrations were not different between MORs and NORs (P > 0.05). Concentrations of testosterone in the spermatic vein of FORs (127 ± 66 ng/ml) were greater (P <0.05) than in MORs (41 ± 10 ng/ml) and NORs (19 ± 7 ng/ml). Serum LH concentrations were not different. Cortisol was higher (P <0.05) in anesthetized MORs (25.1 ± 4.2 ng/ml) and NORs (27.2 ± 4.4 ng/ml) than in FORs (10.9 ± 1.8 ng/ml). These results demonstrate that circulating testosterone concentrations are related to sexual behavior only when rams are bled under anesthesia. Thus, differences in basal androgen concentrations in adulthood cannot be responsible for expression of male-oriented preferences or low libido in sheep. Instead, functional differences must exist between the brains of rams that differ in sexual preference expression.

Original languageEnglish (US)
Pages (from-to)263-268
Number of pages6
JournalBiology of Reproduction
Volume67
Issue number1
StatePublished - 2002

Fingerprint

Testosterone
Serum
Sexual Behavior
Breeding
Libido
Sexual Partners
Androgens
Hydrocortisone
Spermatozoa
Veins
Sheep
Anesthesia
Brain

Keywords

  • Behavior
  • Male sexual function
  • Neuroendocrinology
  • Stress
  • Testosterone

ASJC Scopus subject areas

  • Cell Biology
  • Developmental Biology
  • Embryology

Cite this

Roselli, C., Stormshak, F., Stellflug, J. N., & Resko, J. A. (2002). Relationship of serum testosterone concentrations to mate preferences in rams. Biology of Reproduction, 67(1), 263-268.

Relationship of serum testosterone concentrations to mate preferences in rams. / Roselli, Charles; Stormshak, Fred; Stellflug, John N.; Resko, John A.

In: Biology of Reproduction, Vol. 67, No. 1, 2002, p. 263-268.

Research output: Contribution to journalArticle

Roselli, C, Stormshak, F, Stellflug, JN & Resko, JA 2002, 'Relationship of serum testosterone concentrations to mate preferences in rams', Biology of Reproduction, vol. 67, no. 1, pp. 263-268.
Roselli, Charles ; Stormshak, Fred ; Stellflug, John N. ; Resko, John A. / Relationship of serum testosterone concentrations to mate preferences in rams. In: Biology of Reproduction. 2002 ; Vol. 67, No. 1. pp. 263-268.
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