Light and ultrastructural immunocytochemical study of somatotropic cells (GH cells) in ovine adenohypophysis: lactation and weaning influences

Abstract

The influence of lactation period and weaning on the distribution, number, and structure of somatotropic cells (GH cells) in ewes was studied using immunocytochemical procedures for light and electron microscopy, as well as morphometric and stereological techniques. The adenohypophyseal gland of 12 ewes of the Segureña breed in different stages of milk production and weaning was studied, while three ewes in anoestrus served as controls. The size of secretory granules was heterogeneous in all stages, suggesting that this characteristic is not related to functional activity. During lactation and weaning the size of GH cells decreased, while the number of 'synthesis cells' increased. The rough endoplasmic reticulum and Golgi complex appeared more developed and small secretory granules showed lower gold particle labelling. These data suggest that GH cells are more active during lactation, particularly during late lactation.

Immunocytochemical Light- and Electron-Microscopic Studies of Growth Hormone, Prolactin and Somatomammotroph Cells in Female Goat

“…These results agree with earlier reports of Navarro [1987] in goat. Changes are also found in cell types, type II predominating in all stages and type I increasing markedly during lactation, as noted by Bernabé et al [2000] in sheep.…”

“…They are more frequent than GH cells at all stages. The percentage of GH cells decrease from prepuberty to lactating goats, as reported by Gó mez et al [1989], Singh and Dhingra [1979] and Bernabé et al [2000]. The higher number of PRL cells in prepubertal goats may be related to different physiological stages, such as the development of the mammary gland [Topper and Freeman, 1980], the release of other hormones (GH, ACTH and TSH) or the regulation of the immune system [Esquifino et al, 1989].…”

“…The size, number and ultrastructural characteristics (development of endoplasmic reticulum, Golgi complex and secretory granules) of hormonal cells are the principal characteristics which have been studied in the different physiological conditions relating to prepubertal, anestrus, pregnancy and lactation stages [Navarro, 1987;Vila-Porcile et al, 1988;Takahashi, 1991;Kurosumi, 1991;Sá nchez et al, 1992Sá nchez et al, , 1993Bernabé et al, 1997Bernabé et al, , 2000. In PRL cells of the rat Boockfor and Frawley [1987] described differences in the localization of the adenohypophysary cells within the glandule, a finding that remains to be corroborated in the female goat.…”

Light and Ultrastructural Immunocytochemical Study of Prolactin Cells in Ovine Adenohypophysis

“…This study completes a series dedicated to analyzing the influence of SMT cells [Bernabé et al, 1997] and GH cells [Bernabé et al, 2000] on milk production.…”

Estudo quantitativo das células granulares adenohipofisárias associadas à produção do hormônio de crescimento e avaliação do perfil bioquímico do IGF-I em cães Golden Retriever com Distrofia Muscular (GRMD)

“…As células produtoras de GH estão normalmente localizadas junto aos sinusóides (BERNABÉ et al, 2000;NAKANE, 1970) e variam em sua forma de oval a piramidal com um diâmetro aproximado de 10-13µm em ratos (NAKANE, 1970) (BERNABÉ et al, 2000).…”