Regression of Pathological Changes Induced by Long-Term Administration of Contraceptive Steroids to Rodents

The study investigated the reversibility of pathologic changes in rodents induced by long-term administration of contraceptive steroids, specifically quingestanol acetate and quinestrol, over 50 weeks followed by a 30-week observation period. Significant effects included suppressed body weight gain, reduced food consumption, hair loss, ataxia, mammary chain masses with adenocarcinoma, lens opacities, ovarian atrophy, and uterine atrophy with inflammation. Upon cessation of treatment, body weight and food consumption normalized, mammary masses decreased, adenocarcinomas regressed, and ataxia and pituitary enlargement diminished. However, hair loss and lens opacities persisted. Ovarian and uterine inflammation reduced, with endometrial regeneration and luteal cell presence observed. The study highlighted the potential for regression of certain steroid-induced pathologic and endocrine changes, excluding tegumentary and ocular effects.