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Preputial separation and glans penis changes in normal growing Crj: CD (SD) IGS rats
1Chemicals Assessment Center, Chemicals Evaluation and Research Institute, Hita, Oita1, Japan. yamasaki-kanji@hita.cerij.or.jp
Insights
Preputial separation in Sprague Dawley (SD) rats is linked to changes in glans penis morphology. Complete separation coincides with a flattened glans surface, observed by postnatal day 44.
Area of Science:
- Developmental Biology
- Comparative Anatomy
- Rodent Models
Background:
- Understanding male reproductive development is crucial.
- Preputial separation is a key maturational event in rodents.
- Morphological changes in the glans penis accompany this process.
Purpose of the Study:
- To document the timeline of preputial separation.
- To characterize age-related changes in glans penis morphology.
- To correlate these events in Sprague Dawley (SD) rats.
Main Methods:
- Longitudinal observation of SD rats from birth to 53 days.
- Detailed examination of glans penis surface morphology.
- Recording the precise day of complete preputial separation.
Main Results:
- Glans penis morphology progresses from a protruding os penis to a W shape, then to a flattened surface.
- The W shape emerged between postnatal days 30-35.
- A flattened surface was observed from postnatal day 39, with full development by day 44.
- Complete preputial separation consistently occurred on the same day the flattened glans surface appeared.
Conclusions:
- Preputial separation in SD rats is a well-defined event.
- Glans penis morphology undergoes predictable changes during development.
- The appearance of a flattened glans surface is a reliable indicator of complete preputial separation.
Abstract:
This study was designed to detect preputial separation and glans penis changes in normal growing SD rats. We examined the changes until 53 days after birth. The glans penis surface changed from a protruding os penis structure to a W shape, and from a W shape to a flattened surface with age. The protruding os penis structure changed gradually to the W shape from postnatal day (PND) 30, and all rats had the W shape by PND 35. The flattened surface was observed from PND 39, and all rats had this structure by PND 44. In all rats, the day of complete preputial separation exactly corresponded to the day of appearance of the flattened surface.