Ultrastructural Studies on the Pituitary Gland of Pig ( Sus scrofa domestica )

Among domestic animals, pigs serve as valuable biomodels for studying endocrine disorders due to similarities in the structure and hormone production of their pituitary gland with humans. The pituitary gland is a central regulator of hormonal balance and plays a crucial role in various physiological functions. The present ultrastructural studies of the porcine pituitary gland not only enhance our understanding of porcine anatomy but also provide valuable comparative data for understanding the functioning of the human pituitary gland. The pituitary gland of the pig consisted of adenohypophysis and neurohypophysis. The adenohypophysis was differentiated into pars distalis, pars intermedia, and pars tuberalis, while the neurohypophysis was divided into median eminence, infundibular stalk, and pars nervosa. Each lobe had a wide variety of hormone-secreting cells. The somatotrophs contained numerous electron-dense round secretory granules and rough endoplasmic reticula. The lactotrophs contained large electron-dense secretory granules in different shapes. The thyrotrophs contained smaller secretory granules with few mitochondria and Golgi complex. The gonadotrophs contained round electron-dense to electron-lucid secretory granules. The corticotrophs contained numerous round to oval-shaped electron-dense secretory granules and more of Golgi complex and mitochondria. In pars intermedia, granular cells, non-granular cells, elongated cells, interstitial cells, and the cleft lining cells with microvilli were noticed, whereas in the pars tuberalis, granulated cells, non-granulated cells and interstitial cells were observed. In the pars nervosa, numerous bundles of non-myelinated axons and few myelinated axons along with pituicytes were noticed. The axon terminals contained electron-dense to electron-lucid Herring bodies and numerous mitochondria.