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The non-aromatizable androgen dihydrotestosterone (DHT) facilitates sexual behavior in ovariectomized female rats primed with estradiol.

Psychoneuroendocrinology. 2020 Feb 07;115:104606

Authors: Maseroli E, Santangelo A, Lara-Fontes B, Quintana GR, Mac Cionnaith CE, Casarrubea M, Ricca V, Maggi M, Vignozzi L, Pfaus JG

Abstract

It is still unclear whether Testosterone (T) increases sexual desire through a stimulation of the androgen receptor in relevant brain regions or through its conversion to estrogens. The aim of this study was to clarify the mechanisms of T facilitation of female sexual desire by assessing the effect of a non-aromatizable androgen (Dihydrotestosterone, DHT) in a validated animal model. Ovariectomized (OVX) Long-Evans rats were treated with oil (O) + O, 10 mcg Estradiol Benzoate (EB) + O, 10 mcg EB?+?500 mcg Progesterone (P), O?+?500 mcg DHT or 10 mcg EB?+?500 mcg DHT (n?=?12 per group). EB was administered 48?h, while P and DHT 4?h, prior to 4 sexual behavioral testing sessions in bisected unilevel pacing chambers. Appetitive behaviors (the frequencies of hops/darts and solicitations) were considered as the main outcome measure. Sexual receptivity indexes [lordosis magnitude, expressed as lordosis rating (LR), and lordosis quotient (LQ)], rejection responses, as well as mounts, intromissions and ejaculations received from the male were also coded. The probability of transition among sexual behaviors was evaluated by Transition Matrices; T-Pattern analysis was performed to detect hidden repeated temporal behavioral sequences. Preliminary analyses found no statistically significant differences between the O?+?O and EB?+?O groups, therefore we excluded the EB?+?O group from further analyses. Rats treated with EB?+?DHT displayed significantly more appetitive behaviors compared to negative controls (O?+?O and O?+?DHT), whereas no difference was observed between EB?+?DHT rats and positive controls (EB?+?P); noteworthy, a higher number of appetitive behaviors was observed in the O?+?DHT group compared to the O?+?O group. Furthermore, rats treated with EB?+?DHT showed significantly higher receptivity measures (LR and LQ) and received more mounts, intromissions and ejaculations compared to negative controls (O?+?O and O?+?DHT), to levels equivalent to EB?+?P. No differences were detected in female-male mounts or rejection responses among the 4 groups. Under a qualitative perspective, full solicitation was found exclusively in T-patterns of the EB?+?DHT group, which was also the only one to display T-patterns of higher order encompassing appetitive behaviors-only events. In conclusion, the administration of DHT in EB-primed OVX Long-Evans rats enhances sexual behavior measures. Specifically, DHT seems to stimulate sequences of appetitive behaviors separated from copulative/reproductive measures. Our data support an independent role of androgens in the facilitation of female sexual desire.

PMID: 32087523 [PubMed - as supplied by publisher]