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M J Erpino

Publications and source records attributed to M J Erpino.

11 recordsLinked to original sources
PubMed1996

Evolution teaching.

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Biological Evolution↗
PubMed1996

Progesterone does not inhibit aggression induced by testosterone metabolites in castrated male mice.

Sufficient data exist indicating that testosterone (T) or metabolites of T, i.e., dihydrotestosterone (DHT) and estrogen (E), induce aggressive behavior. The effects of T have also been shown to be suppressed by concurrent administration of progesterone (P). It is unknown if the effects of P are exerted on T directly or upon the T metabolites. The objective of this experiment was to evaluate the inhibitory effects of P on aggression induced by T and T metabolites. Seven male mice were randomly allocated to one of the following treatment groups: castration (C), C + T, C + 5 alpha-dihydrotestosterone (DHT), C + estrogen (E), C + DHT + E (DE), T + P, and DE + P. The males were then placed with androgenized females in three 10-min trials to determine the effects of each treatment on hormone induced aggression. The degree of aggressive behavior displayed was measured by number of trials where attacks occurred (N), mean latency to attack (L), frequency of attacks (AF), duration of attacks (D), and a composite index score (INDEX). All androgen treated groups showed significantly higher degrees of aggression compared to C and T + P animals. P inhibited aggression in T-treated males but did not inhibit aggression in the DE treated group. The data suggest that P inhibits the aggressive effects of T by acting on receptors of the metabolite-producing enzymes or by direct competitive binding for 5 alpha-reductase.

Aggression↗
PubMed1977

Progestagen effects on elicitation of aggressive behaviour in male mice.

Effects of progesterone on production of androgen-dependent aggression-eliciting pheromones were investigated. Two groups of anosmic (non-fighting) castrated mice treated with testosterone or with testosterone and progesterone, respectively, were attacked to the same degree by intact, isolated (fighting) mice while control mice (castrated only) were attacked less. The findings support the ideas that progesterone may inhibit androgen-induced aggression via a neural and not via a somatic mechanism.

Aggression↗