Media for animal cell culture

Modern principles of classification and development of nutrient media for culturing of human and animal cells

Analysis of the main principles of classification and development of nutrient media used for culturing of human and animal cells in biology and medicine is presented. The key moments of induction and regulation of mitogenic cascades and their differences in cells of continuous lines, diploid cells, and primary cultures are discussed. Some variants of classification of nutrient media for various cell culture types are described. Peculiarities of composition and the prospects of using serum-free media are discussed. Practical results obtained by the authors in the development of diverse purpose nutrient media are presented.

Glucocorticoid receptors in epithelial cells isolated from the mammary glands of pregnant and lactating rats

We have isolated epithelial cell clusters from mammary glands of pregnant and lactating rats by collagenase-hyaluronidase-deoxyribonuclease digestion, followed by Ficoll density-gradient centrifugation. Clusters of greater than 90% viable cells were identified by light microscopy as essentially devoid of other cell types; the integrity of their subcellular organelles verified by electron microscopy. Binding characteristics of the synthetic glucocorticoid [3H]dexamethasone were studied in cytosols prepared from isolated cell clusters. Cytosols from both pregnant and lactating rats bound [3H]dexamethasone with high affinity to a single class of low capacity binding sites. In both types of cytosol the dissociation constant (Kd 4 degrees C approximately/nM) of the binding was similar; the number of sites per cell in lactating rats was approximately double that in pregnant rats. The specificity of binding was typical of a classical glucocorticoid receptor, with a hierarchy of affinity by competition studies dexamethasone greater than progesterone greater than aldosterone much much greater than testosterone = estradiol. In particular, no difference in progesterone affinity for these glucocorticoid receptors was seen between pregnancy and lactation. This suggests that reported differences in inhibitory action of progesterone, pregnancy versus post-partum, are not glucocorticoid-receptor mediated.