Cortisol, growth hormone, and testosterone concentrations during mating behavior in the bull and boar.

Abstract

Two experiments were conducted to evaluate peripheral concentrations of cortisol (C), growth hormone (GH), and testosterone (T) in bulls and boars during mating and to correlate mating behaviors with endocrine secretion in the presence of an estrous female. In Exp. 1, six sexually inexperienced mature bulls were bled every 15 min for 2 h before and 2 h after a 30-min exposure to a single, restrained, estrous cow; sampling occurred every 5 min during exposure. In Exp. 2, six sexually experienced boars were bled similarly before and after exposure to a sow and every 5 min during a 15-min exposure to a freely moving, estrous sow. Behavioral events recorded during exposure to a female included the following: flehmen responses (bulls only), mounts, penis extensions, intromissions, ejaculations, and time to first mount and first ejaculation. Of the six bulls, four completed at least one service (intromission + ejaculation), and three of six mounted the estrous cow eight or more times. Completion of one or more services resulted in significant elevations in serum C and GH concentrations, but not T concentrations, during the exposure period. Bulls mounting eight or more times also experienced significant elevations in C concentrations during exposure. Three of six boars completed at least one service. Servicing and mounting the sow fewer than five times were both associated with significant elevations in serum C concentrations. Serum concentrations of T were also elevated as a result of exposure to an estrous sow. Collectively, these data support the suggestion that specific events during natural mating activity can alter endocrine secretions of C and GH in bulls and C and T in boars.

Effects of Mating on Plasma Concentrations of Testosterone, Cortisol, Oestrone Sulphate and 15‐Ketodihydro‐PGF2α in Stallions

“…1977; Kamel and Frankel 1978). A similar hormonal response has been observed in pigs (Borg et al. 1991) and rabbits (Agmo 1976).…”

Plasma levels of corticosterone and testosterone after sexual activity in male rats treated neonatally with clomipramine

“…This finding is similar to that reported for several mammalian species (Szachman et al, 1974;Agmo, 1976;Kamel and Frankel, 1978;Bronson and Desjardins, 1982;Rabb et al, 1989;Borg et al, 1991;Retana-Márquez et al, 1998). However, the physiological significance of these increases has not been elucidated.…”

“…However, it has been shown that there is an increase of both corticosterone and testosterone after masculine sexual behavior in several mammal species (Szachman et al, 1974;Agmo, 1976;Kamel and Frankel, 1978;Rabb et al, 1989;Borg et al, 1991;Retana-Márquez et al, 1998), suggesting that both axes are activated simultaneously by sexual behavior.…”

Distribution of gonadal steroid receptor–containing neurons in the preoptic–periaqueductal gray–brainstem pathway: A potential circuit for the initiation of male sexual behavior

“…Although plasma testosterone levels do not fluctuate in a consistent pattern during male reproductive behavior (Kamel et al, 1977;Lunstra et al, 1989;Borg et al, 1991), it is possible that during copulation, local changes in testosterone or estrogen binding to the ER␣ and AR receptors identified within the MPO3 PAG3nPGi circuit are involved in ligand-dependent transcriptional events, thereby influencing the expression of various neurotransmitters and ultimately facilitating reproduction. Alternatively, steroid binding to the ER␣-and AR-containing neurons localized within the MPO3 PAG3nPGi pathway may play a permissive role in copulation by maintaining neuronal viability within this circuit.…”