Novel males' capacity to disrupt early pregnancy in mice (Mus musculus) is attenuated via a chronic reduction of males' urinary 17beta-estradiol.
Mature male mice of proven fertility were administered chronic oral doses of anastrozole, a potent aromatase inhibitor, and also given a low-phytoestrogen diet. Urine was taken non-invasively from such males and from untreated control males and assayed for 17beta-estradiol and testosterone via ELISA procedures. After 8 weeks of drug or vehicle administration, urinary 17beta-estradiol declined to significantly lower levels in anastrozole-treated males than in non-treated males, whereas testosterone levels were comparable in the two groups. Inseminated females were exposed to drug-treated, vehicle-treated, or no males during days 1-6 of gestation, around intrauterine implantation of fertilized ova. Females exposed to vehicle-treated males produced fewer litters than did those kept in isolation. Females exposed to anastrozole-treated males produced significantly more litters than did those exposed to vehicle-treated males. These data support the notion that male excretions of estrogens may in part mediate novel-male-induced pregnancy disruptions, although other influences of aromatization on behaviour and metabolism remain possibilities.
Beaton
Elliott A
EA
Department of Psychology, McMaster University, Hamilton, Ont., Canada L8S 4K1.
deCatanzaro
Denys
D
D000077384:Anastrozole; D000818:Animals; D001141:Aromatase / Q000378:metabolism; D004032:Diet; D010064:Embryo Implantation / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004958:Estradiol / Q000652:urine*; D004965:Estrogen Antagonists / Q000494:pharmacology*; D005260:Female; D005298:Fertility / Q000187:drug effects; D007314:Insemination; D008297:Male; D051379:Mice; D009570:Nitriles / Q000494:pharmacology; D048789:Phytoestrogens / Q000494:pharmacology; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology* / Q000523:psychology; D012934:Social Isolation; D013739:Testosterone / Q000097:blood; D014230:Triazoles / Q000494:pharmacology
D004791:Enzyme Inhibitors; D004965:Estrogen Antagonists; D009570:Nitriles; D048789:Phytoestrogens; D014230:Triazoles; D000077384:Anastrozole; D013739:Testosterone; D004958:Estradiol; D001141:Aromatase