title: [Structural characteristics of the thyroid and parathyroid C cells of monkeys during head-down tilt hypokinesia].
abstract: Eight monkeys Macaca rhesus were exposed to head-down tilt for 7 days and to clinostatic hypokinesia for 7 days with subsequent 12-day head-down tilt. C cells of the thyroid gland and the parathyroid glands of 5 control and 8 experimental monkeys were investigated histologically, morphometrically and electron-microscopically. On the 7th tilt day the C cell population increased, their nuclei grew significantly, synthesis activated, and secretory granules accumulated. By day 19 most C cells were in the secretion stage. Morphological signs of an increased functional activity of the thyroid gland were seen on experimental day 7 and those of the parathyroid gland on day 19, both in light and electron microscopies. Taking into account the antagonism of C cells and parathyroid glands, it can be assumed that the hypocalcemic effect of calcitonin plays a part in the stimulation of parathyroid glands during head-down tilt.
mesh_terms: D000818:Animals; D008253:Macaca mulatta; D008297:Male; D008854:Microscopy, Electron; D010280:Parathyroid Glands / Q000473:pathology*; D011187:Posture; D012149:Restraint, Physical; D013961:Thyroid Gland / Q000473:pathology*; D013997:Time Factors
vernacular_title: Strukturnye osobennosti C-kletok shchitovidnoĭ zhelezy i parashchitovidnykh zhelez obez'ian pri antiortostaticheskoĭ gipokinezii.