Lipogenic enzyme and apoprotein messenger RNAs in long-term primary culture of chicken hepatocytes

Hepatocytes isolated from 9-week-old chickens were cultured in a serum-free, hormonally defined medium. Relative amounts of mRNAs coding for lipogenic enzymes (acetyl-CoA carboxylase, fatty acid synthase, delta 9 desaturase, malic enzyme) and apoproteins (apoprotein A1 and apoprotein B) were determined until the 12th day. beta-actin and albumin mRNA, as well as albumin secretion, were also assessed. Cellular metabolic activity appeared to be very low for the first days of culture, but increased after the 7th day. All the mRNAs studied, except for that of malic enzyme, were present from this time throughout the culture lifespan. The biological significance of the observed results and the relevance of this chicken hepatocyte culture system for long-term metabolic and genetic studies are discussed.

Evidence of a functional aromatase system in the pituitary gland of the chick embryo in vitro

ABSTRACT The in-vitro effects of oestradiol and testosterone, alone or together with an aromatase inhibitor (1,4,6-androstatriene-3,17-dione), on the appearance of progesterone receptor (PR) in the pituitary were studied in the chick embryo. Whole pituitary glands from 10-day-old embryos were cultured for 2 days in a hormonally defined medium. The oestrogenic activity of the hormone added to the medium was determined by the induction of PR in nuclei of pituitary cells. Cells containing PR were identified by immunohistochemistry with an antibody to PR. Pituitary cells contained PR in their nuclei after 48 h of incubation with oestradiol or testosterone (0·1 μmol/l). Dihydrotestosterone failed to induce PR in pituitary cells, as did testosterone if the aromatase inhibitor was added to the culture medium. It is concluded that testosterone is aromatized locally at the level of the pituitary and, consequently, acts through the oestradiol receptor to induce the appearance of PR in pituitary cells. J. Endocr. (1988) 119, 229–232

Regulation of insulin mRNA abundance and adenylation: dependence on hormones and matrix substrata

The insulin mRNA levels of rat insulinoma cell lines increased six- to eightfold, and the cells entered a transient state of growth arrest when they were cultured in serum-free, hormonally defined medium and on an extract of extracellular matrix derived from a basement membrane-secreting tumor line, EHS. Insulinoma cultures in growth arrest responded to glucose with a two- to threefold increase in insulin secretion associated with an insulin mRNA that contained a poly(A) tail that was 120 to 140 bases longer than normal.

Regulation of insulin mRNA abundance and adenylation: dependence on hormones and matrix substrata.

The insulin mRNA levels of rat insulinoma cell lines increased six- to eightfold, and the cells entered a transient state of growth arrest when they were cultured in serum-free, hormonally defined medium and on an extract of extracellular matrix derived from a basement membrane-secreting tumor line, EHS. Insulinoma cultures in growth arrest responded to glucose with a two- to threefold increase in insulin secretion associated with an insulin mRNA that contained a poly(A) tail that was 120 to 140 bases longer than normal.