Cytomorphological and morphometric studies of somatotrophs in the pituitary pars distalis of postnatal female albino rats

Abstract EN

The present study was designed to demonstrate the cytomorphological and morphometric changes of somatotrophs in female rats during the postnatal period by using the light and transmission electron microscopy.

Fifty female rats were used in this study which classified into age ten groups (5 animals / group) (neonate, 7, 15, 22, 30 & 40 days-old rats); adults (2, 4 & 6 months-old rats) and senile (2 years-old rats).

All animals were sacrificed and their pituitary glands immediately dissected, fixed and processed for light and electron microscopy.

At the first week of postnatal life, somatotrophs were scanty and showed signs of inactivity.

They were revealed as sporadic, small-sized round or triangular-shaped cells with faint yellow stained cytoplasm after staining with PAS-Orange G.

Ultrastructurally, it showed few secretory granules and ill-developed cytoplasmic organelles.

With age, a significant increase in the number of somatotrophs associated with increasing in the secretory activity and organelles at the immature stage till reaches its maximum in adults.

At 22-30 days-old rats, two types of somatotrophs were seen ultrastructurally; densely granulated and sparsely granulated type.

No significant change in the number of somatotrophs was observed at the pubertal stage and most of somatotrophs appeared in the storage phase exhibiting by heavily granulated cytoplasm with ill-distinct organelles.

While in senile rats, a significant decrease in the number of somatotrophs that exhibited signs of inactivity was observed.

They showed some regressive changes including vacuolated cytoplasm, decreasing in granulation with degenerated organelles.

In conclusion, there was a significant postnatal age-related change in the structure and number of somatotrophs in female ratsز