Ultrastructure of the pars intermedia of the developing sheep hypophysis

Cell and Tissue Research
R A PerryG B Ryan


Using light and electron microscopy, the morphogenesis of the pars intermedia of the sheep pituitary gland was examined in developing lambs between 26 days of gestation and the newborn stage. Following the establishment of contact between the anterior and posterior lobe primordia seen at 26 days, the connection with the pharyngeal roof disappeared by 31 days. The lumen of Rathke's pouch, which was a prominent cavity at the earlier stages, became inconspicuous by 40 days but progressively increased in size during gestation and, in some newborn animals, contained colloid material. At 40 days the pars intermedia consisted of a uniform population of undifferentiated cells. Cells with cytoplasmic granules were first identified at 50 days. The cytological appearance of granular cells at 70 days indicated increased synthetic activity and by 80 days they closely resembled adult glandular cells. At 100 days, membrane activity suggestive of exocytosis was first observed in granular cells; fenestrated capillaries were present, and early follicle formation between adjacent non-granular cells was seen. This apparent exocytotic release of granules was observed much more frequently between 100 days of gestation and the newborn stage than in a...Continue Reading


Oct 1, 1978·Proceedings of the National Academy of Sciences of the United States of America·P CrineM Chrétien
Apr 1, 1979·The Journal of Endocrinology·R E SilmanP Nathanielsz
Jan 1, 1974·Acta Endocrinologica. Supplementum·C Svalander
Aug 15, 1967·American Journal of Obstetrics and Gynecology·G C LigginsL W Holm
Dec 1, 1968·Archivum Histologicum Japonicum = Nihon Soshikigaku Kiroku·M MurakamiS Hirata
Jan 1, 1981·Annual Review of Biochemistry·B M Pearse, M S Bretscher
Jan 1, 1981·Cell and Tissue Research·R A PerryG B Ryan


May 1, 1983·Stain Technology·P J McMillanJ McMillan

Related Concepts

Cell Differentiation Process
Plasma Membrane
Cytoplasmic Granules
Endoplasmic Reticulum
Golgi Apparatus
Intercellular Junctions
Electron Microscopy
Pituitary Stalk

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