Mitotic index and cell nuclear volume of zona fasciculata externa in processes of postnatal growth of rat adrenals.

Mitotic index and nuclear volume of the zona fasciculata externa have been studied using male and female Wistar rats weighing 20, 50, 100, 250 and 300 g. Adrenal weight of females was greater than of males. Early postnatal growth of adrenals was attained at the expense of intensity of mitotic division. With age mitotic division decreased but cell hypertrophy developed. Cell hypertrophy in females began at an early age and was more marked than in males.