Serum 5 alpha-androstane-3 alpha, 17 beta-diol increases in response to paced coital stimulation in cycling female rats.
The cycling female rat spontaneously regulates (paces) the amount and timing of cervical-vaginal stimulation received during mating. Female pacing of coital contacts increases the ability of vaginal intromissions to induce luteal function and to abbreviate the period of behavioral estrus. In the experiments reported here, we examined whether paced mating results in alterations in serum steroid concentrations, which might contribute to these processes. In Experiment 1, estradiol (E2), progesterone (P), testosterone (T), 5 alpha-dihydrotestosterone (DHT), and 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-androstanediol, 3 alpha-diol) were measured in sera obtained from independent groups of animals between 0 min and 12 h after mating onset. Levels of 3 alpha-diol were significantly higher at 30 min in females pacing coital stimulation (Paced) than in females receiving mounts-without-intromission (Mounts-Only) or solitary exposure to the test chamber. Serum T, E2, P, and DHT did not differ between these groups at any time. P and 3 alpha-diol levels declined significantly for all groups across the 12-h post-treatment period. In Experiment 2, serum 3 alpha-diol measured over 3h after mating was compared in females receiving Paced stimulation with females receiving temporally unregulated coital stimulation (Non-Paced), or Mounts-Only. At 20 min, serum 3 alpha-diol concentrations were significantly higher in Paced than in Non-Paced and Mounts-Only females. In Experiment 3, Paced and Non-Paced stimulation did not differentially effect the proportion of females becoming pseudopregnant/pregnant. The selective increase in serum 3 alpha-diol in females that pace matings is discussed with regard to the known inhibitory effects of 5 alpha-reduced androgens on sexual receptivity.
Erskine
M S
MS
Department of Applied Biological Sciences, Massachusetts Institute of Technology, Cambridge 02139.
D015113:Androstane-3,17-diol / Q000097:blood*; D000732:Androstanols / Q000097:blood*; D000818:Animals; D003307:Copulation / Q000502:physiology*; D013196:Dihydrotestosterone / Q000097:blood; D004958:Estradiol / Q000097:blood; D004971:Estrus / Q000097:blood / Q000502:physiology*; D005260:Female; D008297:Male; D011374:Progesterone / Q000097:blood; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D012726:Sexual Behavior, Animal / Q000502:physiology; D013739:Testosterone / Q000097:blood
D000732:Androstanols; D013196:Dihydrotestosterone; D015113:Androstane-3,17-diol; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol