Formation of Centrioles in Some Endocrine Adenomas

Centrioles, known to play a fundamental role in mitotic division, are regarded as representing self-replicating organelles. They occur with varying frequency in different normal cells and exhibit uniform appearances showing no signs indicative of duplication such as budding or division. In order to obtain a deeper insight into centriole formation and evolution, cases of parathyroid and pituitary adenomas with a high centriole population were investigated by electron microscopy.The material used for the present study consisted of 4 chief cell adenomas of the parathyroid gland, 7 sparsely granulated pituitary growth hormone cell adenomas and 1 mixed cell pituitary adenoma composed of sparsely granulated growth hormone cells and prolactin cells. These adenomas were selected from a large number of cases (26 parathyroid adenomas and 49 pituitary adenomas). All specimens were obtained by surgery from various patients with hyperparathyroidism or acromegaly. Small pieces of tissue were fixed immediately after removal in 2.5 per cent glutaraldehyde in Sorensen's buffer, postfixed in 1 per cent osmium tetroxide in Millonig's buffer, dehydrated in graded ethanol and embedded in Epon 812.

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Experimental modification of rat pituitary growth hormone cell function during and after spaceflight

Journal of Applied Physiology ◽

10.1152/jappl.1996.80.3.955 ◽

1996 ◽

Vol 80 (3) ◽

pp. 955-970 ◽

Cited By ~ 20

Author(s):

W. C. Hymer ◽

R. E. Grindeland ◽

T. Salada ◽

P. Nye ◽

E. J. Grossman ◽

...

Keyword(s):

Growth Hormone ◽

Cell Function ◽

Cell Types ◽

Secretory Cells ◽

Mixed Cell ◽

Pituitary Growth Hormone ◽

Gh Cells ◽

Growth Hormone Cell ◽

And Function

Space-flown rats show a number of flight-induced changes in the structure and function of pituitary growth hormone (GH) cells after in vitro postflight testing (W. C. Hymen, R. E. Grindeland, I. Krasnov, I, Victorov, K. Motter, P. Mukherjee, K. Shellenberger, and M. Vasques. J. Appl. Physiol. 73, Suppl.: 151S-157S, 1992). To evaluate the possible effects of microgravity on growth hormone (GH) cells themselves, freshly dispersed rat anterior pituitary gland cells were seeded into vials containing serum +/- microM hydrocortisone (HC) before flight. Five different cell preparations were used: the entire mixed-cell population of various hormone-producing cell types, cells of density < 1.071 g/cm3 (band 1), cells of density > 1.071 g/cm3 (band 2), and cells prepared from either the dorsal or ventral part of the gland. Relative to ground control samples, bioactive GH released from dense cells during flight was reduced in HC-free medium but was increased in HC-containing medium. Band 1 and mixed cells usually showed opposite HC-dependent responses. Release of bioactive GH from ventral flight cells was lower; postflight responses to GH-releasing hormone challenge were reduced, and the cytoplasmic area occupied by GH in the dense cells was greater. Collectively, the data show that the chemistry and cellular makeup of the culture system modifies the response of GH cells to microgravity. As such, these cells offer a system to identify gravisensing mechanisms in secretory cells in future microgravity research.

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