02-103 Sigma-AldrichBovine Pituitary Extract - 50 mg

Hepatocytes were isolated from human fetal liver in order to analyze the direct effects of growth factors and hormones on human hepatocyte proliferation and function. Mechanical fragmentation and then dissociation of fetal liver tissue with a collagenase/dispase mixture resulted in high yield and viability of hepatocytes. Hepatocytes were selected in arginine-free, ornithine-supplemented medium and defined by morphology, albumin production and ornithine uptake into cellular protein. A screen of over twenty growth factors, hormones, mitogenic agents and crude organ and cell extracts for effect on the stimulation of hepatocyte growth revealed that EGF, insulin, dexamethasone, and factors concentrated in bovine neural extract and hepatoma cell-conditioned medium supported attachment, maintenance and growth of hepatocytes on a collagen-coated substratum. The population of cells selected and defined as differentiated hepatocytes had a proliferative potential of about 4 cumulative population doublings. EGF and insulin synergistically stimulated DNA synthesis in the absence of other hormones and growth factors. Although neural extracts enhanced hepatocyte number, no effect on DNA synthesis of neural extracts or purified heparin-binding growth factors from neural extracts could be demonstrated in the absence or presence of defined hormones, hepatoma-conditioned medium or serum. Hepatoma cell-conditioned medium had the largest impact on both hepatocyte cell number and DNA synthesis under all conditions. Dialyzed serum protein (1 mg/ml) at 10 times higher protein concentration had a similar effect to hepatoma cell-conditioned medium (100 micrograms/ml). The results suggest that hepatoma cell conditioned medium may be a concentrated and less complicated source than serum for purification and characterization of additional normal hepatocyte growth factors.

Selective nutritive conditions were used to isolate normal epithelial cells from fibroblasts in primary cell cultures prepared from adult rat prostate. The pure population of normal epithelial cells proliferated at an exponential rate on a simple polystyrene substratum with doubling times of 35 to 50 hr for 10 to 12 days in the absence of high epithelial cell density, other cell types, or added extracellular matrix elements. Optimization of the nutritive environment allowed direct analysis of the hormone:growth factor requirements for sustained proliferation of the isolated epithelial cells in serum-free medium. An in situ videometric method was used to assay the effect of over 30 known hormones and growth factors on proliferation of the prostate epithelial cell population. The results revealed direct mitogenic effects of insulin, epidermal growth factor, glucocorticoid, cholera toxin, one or more unidentified factors from bovine pituitary, and possibly prolactin. No direct mitogenic effect of androgen on isolated prostate epithelial cells could be demonstrated. Radioimmunoassay of androgen in the primary cultures showed that endogenous androgen was about 34 pM on Day 1 of culture and thus probably too low to mask a response to exogenous androgen. Deletion of any single active growth factor did not reveal an androgen response. The results demonstrate a multihormonal control of normal prostate epithelial cell maintenance and proliferation without the direct participation of androgen.

Colony formation by normal human epidermal keratinocytes (HK) has been achieved in a medium that contains no deliberately added undefined supplements. The term "defined" is used to describe this medium, although the possibility that trace contaminants in its components could be contributing to the multiplication that it supports cannot yet be ruled out completely. The defined medium consists of a basal medium, MCDB 152, supplemented with 5 ng/ml epidermal growth factor (EGF), 10 micrograms/ml transferrin, 5 micrograms/ml insulin, 1.4 X 10(-6) M hydrocortisone, 1.0 X 10(-5) Methanolamine, 1.0 X 10(-5) M phosphoethanolamine, and 2.0 X 10(-9) M progesterone. MCDB 152 differs from MCDB 151, previously developed for multiplication of HK with small amounts of dialyzed serum (Peehl and Ham, 1980b), only by addition of the trace element mixture from human fibroblast medium MCDB 104 (McKeehan et al., 1977). Most of the requirement for transferrin, which is the least defined component of the defined medium, can be replaced by adding freshly dissolved and sterilized ferrous sulfate to the final medium after it has been filter sterilized. Insulin and EGF are clearly needed for optimal multiplication and hydrocortisone is mildly beneficial. Either ethanolamine or phosphoethanolamine must be present in the defined medium for HK multiplication. There is a greater need for EGF and less for hydrocortisone in the defined medium than in previous partially defined systems that we have worked with. Very large colonies of flattened epithelial cells are obtained in the defined medium, which has a low calcium concentration (0.03 mM) and does not favor keratinocyte differentiation. Less growth and more differentiation are obtained with higher calcium concentrations. The defined medium is highly selective for keratinocyte growth from a mixed inoculum of keratinocytes and fibroblasts.