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Biomedical subjects

A V Tkachev

Publications and source records attributed to A V Tkachev.

At least 37 records · Page 2Linked to original sources
PubMed1982

[Ultrastructural characteristics of the differentiation of glandular cells in the anterior pituitary gland of collared lemmings (Dicrostonyx) from the Vrangel Island].

In 15.5-, 16-, 17.5-, 18.5-, 20-day-old fetuses and newborn lemmings, the ultrastructure of the anterior lobe of the hypophysis has been studied. In the parenchyma of the 15.5-day-old fetus gland, some cells containing secretory material are revealed, but they are difficult for identification, since differentiation of their organellas is not completed and polymorphism of their granules is strongly manifested. On the 17.5th day of the prenatal development TTH-, ACTH-, LH-, STH-secreting adenocytes are detected; they include secretory granules having diameters 70--100 nm, 80--150 nm, 60--140 nm and 200--400 nm, respectively. On the 18.5th day FSH-secreting cells are identified. Lactotropocytes appear on the 20th day. The anterior lobe of the hypophysis of 17.5--18.5-day-old fetuses are characterized by a high level of the secretory activity which decreases to some extent before birth. Ultrastructure of the cellular organellas in the newborn hypophysis is similar to that in a mature animal, nevertheless, the diameter of the secretory granules does not reach the size of these elements in mature individuals.

Adrenocorticotropic Hormone↗
PubMed1981

[Histological and ultrastructural analysis of the adrenal cortex of the Wrangel Island hoofed lemming (Dicrostonyx torquatus vinogradovi Ognev, 1948)].

Structure of the adrenal cortex of the lemming (Dicrostonyx torquatus vinogradovi Ognev, 1948) from the Wrangel Island has been studied light optically and electron microscopically. Histological investigation of the adrenals has revealed some peculiar features in the gland demonstrating a moderate development of the reticular zone in both sex in the Dicrostonyx torquatus, as well as certain sex dimorphism in the organ's structure. A smaller specific gravity of the female glomerular zone, division of the female glomerular zone into two morphologically heterogenous layers and more distinctive medullary capsule in the males should be mentioned as the distinctive features. During pregnancy the glomerular zone undergoes certain reduction, while the glomerulo-reticular zone hypertrophizes. Electron microscopically it has been revealed: lack of the specific vesicular structure in the mitochondrial crists in the fascicular zone cells, an increased contents of myelin-like and vascular formations in mitochondria of the fascicular and reticular zones, a large amount of dark degenerating cells in the reticular zone, as well as a moderate amount of liposomes in corticocytes. Owing to these factors, it is possible to suggest an increased level of steroid processes in the lemming adrenal cortex.

Adrenal Cortex↗