Testosterone-dependent non-copulatory behaviour in male hamsters (Mesocricetus auratus)

Abstract

Male hamsters (intact, castrated or testosterone-treated) were tested for their response to dioestrous and to oestrous females. Response to the dioestrous female was measured in terms of proximity and olfactory investigation; response to the oestrous female was measured in terms of mounting, intromission and ejaculation. Interest in dioestrous females declined in parallel with copulatory behaviour after castration and was restored by implantation of testosterone. Six weeks of testosterone treatment failed to restore copulatory behaviour to pre-castration levels; in contrast, interest in the dioestrous female was fully restored. Different components of the behaviour towards dioestrous female changed at different rates; some were restored within a week of implantation while others took several weeks to reach pre-castration levels. As found previously, the tendencies of the male to approach and to leave the female varied independently.

Precopulatory behaviour in the male hamster: effect of the 5α-reductase inhibitor 17β-N,N-diethylcarbamoyl-4-aza-5α-androstan-3-one

“…Thus 12 mm DHT (representing a ceil¬ ing dose for restoration of sniffing) was less potent than 24 mm DHT in increasing visit length, and was relatively ineffective in decreasing the time spent away from the female. We conclude that the three behav¬ ioural variables have their own separate thresholds of response to 5a-DHT, and this is consistent with the view that these components of sociosexual behaviour can be considered to be independent (Steel, 1982;Steel & Hutchison, 1986).…”

“…In agreement with our study of intact males, this dose level of 4-MA did not affect mean visit length, but significantly increased the mean bouts apart and decreased percentage sniffing. Castration (Steel, 1982) has short-and long-term effects. Mean visit length is markedly reduced within 2 weeks, whilst bouts away from the female lengthen slowly over 5 weeks and sniffing declines over a similar period.…”

“…In the male hamster, three components of precopulatory behaviour, namely the tendencies to approach and to leave the female and to spend time in olfactory investigation, change independently of one another during sexual inter¬ actions and can, therefore, be regarded as a set of in¬ dependent variables (Steel, 1979(Steel, , 1980. All three are reduced after castration, although they decline at dif¬ ferent rates, and can be restored by treatment with testosterone (Steel, 1982). In addition, male hamsters, after exposure to female vaginal secretion, will direct more attention to the donor of the odour than to other mismatching females (Steel, 1984(Steel, , 1985.…”

Odour recognition by male hamsters: discrimination of the hormonal state of females by odour from vaginal secretions

“…Thus, the discrimination between M and MM females was much greater after pre-exposure to the odour of the highly oestrogenized females. Both attraction to the female by odour and the motivation to mate with her are testosterone depend¬ ent (Gregory, Engel & Pfaff, 1975;Steel, 1982). Ex¬ tensive chemical analysis of hamster vaginal secretion and the behavioural activity of its various components (O'Connell, Singer, Pfaffman & Agosta, 1979;Singer, Macrides & Agosta, 1980) has revealed that the attrac¬ tive quality of the discharge lies in the volatile fraction and the sexually arousing quality in the macromolecular fraction (Murphy, 1973;Darby, Devor & Chorover, 1975;Singer, Macrides & Agosta, 1980).…”

“…In a 10-min test with a female, four behavioural measures were taken: percentage of test time spent with the female; mean length of visits to the female; mean length of periods away from the female; percentage of time with the female spent sniffing or licking her. The last three of these measures vary in¬ dependently (Steel, 1982). The method of behavioural testing has been described previously (Steel, 1980(Steel, , 1984.…”