Utility of Orchidometric Parameters for Assessing Sexual Maturation in Male Cynomolgus Macaques ().

Testicular volume is one of several parameters that have been used in preclinical toxicology to facilitate the identification of sexually mature male cynomolgus macaques when semen evaluation is unavailable. Furthermore, testicular volume provides additional information to pathologists to aid in the interpretation of microscopic findings. Orchidometry has been proposed as a useful tool for assessing testicular volume.

Scientific and Regulatory Policy Committee Points to Consider Review: Inclusion of Reproductive and Pathology End Points for Assessment of Reproductive and Developmental Toxicity in Pharmaceutical Drug Development.

Standard components of nonclinical toxicity testing for novel pharmaceuticals include clinical and anatomic pathology, as well as separate evaluation of effects on reproduction and development to inform clinical development and labeling. General study designs in regulatory guidances do not specifically mandate use of pathology or reproductive end points across all study types; thus, inclusion and use of these end points are variable. The Scientific and Regulatory Policy Committee of the Society of Toxicologic Pathology (STP) formed a Working Group to assess the current guidelines and practices on the use of reproductive, anatomic pathology, and clinical pathology end points in general, reproductive, and developmental toxicology studies.

Using Histopathologic Evidence to Differentiate Reproductive Senescence from Xenobiotic Effects in Middle-aged Female Sprague-Dawley Rats.

The female reproductive cycle is orchestrated by cyclical and coordinated hormonal changes under the direction of the hypothalamic-pituitary-gonadal (HPG) axis. Any disruption of the HPG axis may lead to functional and structural alterations in the female reproductive system. Test article-related disturbances in the estrous cycle can be recognized in nonclinical toxicity studies by staging the cycle based on microscopic evaluation of female reproductive organs.

Histologic and cytologic detection of endocrine and reproductive tract effects of exemestane in female rats treated for up to twenty-eight days.

The objective of this study was to determine the shortest period of time necessary to detect histologic evidence of estrous cycle disruption in Sprague-Dawley rats treated for up to 28 days with the aromatase inhibitor exemestane at 1,000 mg/kg. Rats were evaluated on day 5, 8, 15, or 29. Vaginal mucification, uterine and cervical epithelial atrophy, uterine luminal epithelial vacuolation, decreased uterine granulocytes, and hypertrophy/hyperplasia of mammary ducts and alveoli were noted by day 5 and persisted throughout the study.