Abstract
Background:
The urinary system ensures that body fluid, electrolytes, and waste are managed to help keep the body in balance. The kidney, ureters, urinary bladder, and urethra are the components of this system in mammals.

Aim:
In this study, we assessed the development of the urinary system of golden hamsters after birth by assessing morphology, tissue structure, measurements, and cell reactions in both the kidneys and the ureters.

Methods:
A total of 40 golden hamsters were divided into four age groups (7, 14, 21, and 60 days), and examinations were performed using light microscopy. Microscopic Periodic acid–Schiff (PAS) staining showed that there was more basement membrane and glycoprotein production in the tubules and glomeruli.

Results:
Alcian Blue revealed that acidic mucopolysaccharides were collected and increased in the ureter. Masson’s trichrome made it clear that the developing interstitium contained a lot of collagens, while Van Gieson became useful when identifying different tissues, such as muscular and connective tissue. The production of basement membrane and glycoproteins was elevated in the tubules and glomeruli, as indicated by PAS staining. The ureter showed the greatest increase in acidic mucopolysaccharides, as indicated by Alcian blue staining. Moreover, the existence of collagens in the developing interstitium was highlighted, and the delicate structure of glomeruli and tubules in the early life stages revealed a lower degree of development, reaching its peak with age.

Conclusion:
At 1 week after birth, hamster kidneys and ureters produce glomeruli, muscles, and epithelial tissues. At 2 weeks, the kidney and ureter developed well-defined glomeruli, organised tubules, and muscular and connective components, improving nephron function and urine transport. By 3 weeks, the kidney and ureter had mature glomeruli, tubules, and ureter layers for filtration and urine transport. Waste-filtering kidneys and ureters are fully mature at 2 months for hormone regulation.

Key words: Kidney; Ureter; Golden hamster (Mesocricetus auratus); Histochemical stains.