acyline and Body-Weight

The aim of this study was to reproductively assess the clinical and hormonal effects of a GnRH agonist (AG) and an antagonist (AN) administered during the postnatal period in domestic cats. Forty-eight male and female postnatal kittens were randomly assigned to deslorelin acetate 1.6 mg subcutaneous (AG; n = 16), acyline 33 μg/100 g subcutaneous weekly for 3 months (AN; n = 16), or control (CO; n = 16) which remained untreated. The cats were followed up (behavioral observation, physical examination, fecal sexual steroid determinations, mating test, and pregnancy diagnosis) up to puberty. Puberty was delayed (weeks) in the AG animals (62.9 ± 3.5; P < 0.01) but not in the AN (15.5 ± 1.7; P > 0.05) when they were compared with CO kittens (13.4 ± 0.4). Fifteen (15/16) of the AN and CO animals, and only 11 of 16 cats of the AG group were fertile (P > 0.1). No differences were found in body weight (P > 0.1) and measurements (P > 0.1), libido (P > 0.1) and in the appearance of side effects (P > 0.1; except a pyometra in an AG female) among groups. In both AG- and AN-treated males (testosterone; P < 0.01) and females (estradiol-17β; P < 0.01) fecal hormone concentrations were lower than in CO group during the first five postnatal weeks but not later. It is concluded that the neonatal administration of these AG and AN decreased fecal sexual steroids during the first postnatal weeks causing, the agonists but not the antagonist, a significant, reversible delay in puberty appearance.

Topics: Animals; Behavior, Animal; Body Weight; Cats; Contraception; Female; Gonadal Steroid Hormones; Gonadotropin-Releasing Hormone; Male; Oligopeptides; Sexual Maturation; Time Factors; Triptorelin Pamoate

It remains to be established as to whether the absence of estrogen (direct) or the elevated levels of gonadotrophins and androgens (indirect) are responsible for the ArKO (aromatase knockout) ovarian phenotype. The aim of this study was to determine the effects of E(2) (17beta-estradiol) replacement, acyline (GnRH antagonist) and flutamide (anti-androgen) treatment on the ovarian phenotype of ArKO mice. E(2) replacement and acyline treatment but not flutamide treatment, reduced serum gonadotrophin levels of ArKO mice to within normal ranges. E(2) replacement improved uterine and ovarian follicular phenotypes and reduced the number of Sertoli-like filled cords by 62%. Acyline treatment reduced the number of hemorrhagic cysts and the number of Sertoli-like filled cords within ArKO ovaries. The data indicate that the absence of estrogen in concert with elevated levels of circulating gonadotrophins, principally LH, is responsible for the abnormal reproductive phenotype of the female ArKO mouse.

Topics: Animals; Aromatase; Body Weight; Corpus Luteum; Estradiol; Estrogens; Estrous Cycle; Female; Flutamide; Gonadotropins; Immunohistochemistry; Luteinizing Hormone; Mice; Mice, Knockout; Oligopeptides; Organ Size; Ovarian Follicle; Phenotype; Placebos; Protein Transport; SOX9 Transcription Factor; Steroids