Disrupting effect of androgens in postnatal female domestic cats.

To test the hypothesis that in domestic cats, postnatal androgens induce sterility, the aims of this study were to describe the reproductive effects and the clinical safety of a postnatal administration of a long term release androgen in this species. Thirteen newborn littermate female kittens were randomly assigned to one of the following treatment groups within the first 24h of birth: testosterone enanthate 12.5mg sc (TE; n=8) or Placebo (PL; n=5). The animals were subsequently assessed for fecal sexual hormones until puberty was attained and subsequently when matings occurred. After 21 days, ovulation and gestation were diagnosed. All queens were subsequently ovario-hysterectomized. Fecal testosterone concentrations differed between the treatment groups throughout the study period (P<0.05) being greater during the first 2 postnatal weeks in those of the TE group (P<0.01). Fecal estradiol was not affected by treatment (P>0.1). While all the females were receptive during the pubertal estrus (P>0.1), two TE (2/8) compared with all (5/5) females of the PL group had ovulations (P<0.05). Only one (1/2) compared with three (3/5) of the queens of the TE and PL groups, respectively became pregnant. All kittens of the TE group had transient clitoral enlargement. Anovulatory TE-treated cats had no corpus luteum, and a significant diminution of the endometrial glands as well as of the height of the uterine epithelium. It is concluded that, in domestic cats, a single postnatal supra-physiological dose of testosterone caused a large proportion of queens to be anovulatory and there were also histological endometrial abnormalities that also occurred with this treatment that were accompanied by mild and transient side effects.