The proopiomelanocortin (POMC) gene expression of AtT20 mouse pituitary cells is dependent on cell culture conditions.

We have compared the properties of AtT20 cells cultivated in a Dulbecco's modified Eagles medium containing 10% fetal calf serum (FCS) and of AtT20 cells adapted to a chemically better defined medium with transferrin, albumin, insulin, sodium selenit and 0.2% FCS. Our interest was focused on the hypothalamo-pituitary-adrenal axis (HPA) involved adrenocorticotropic hormone (ACTH) and the potent opioid peptide beta-endorphin (beta-END).

Bovine early pregnancy factor (EPF) activity dependent on a 67-kDa polypeptide.

Maternal bovine EPF activity can be reduced to one single polypeptide enriched and identified from serum of cows in early pregnancy. The relative molecular weight of this active polypeptide was estimated at 67 kDa. This bovine EPF was labelled by 125I and peroxidase.

Proliferation of hybridoma cells in low-serum medium.

After stepwise adaptation to PFH-medium with low serum levels over a period of 4 weeks two pools of the IWF-F2 hybridoma have been obtained which can be grown continuously in PFH-medium supplemented with 2 resp. 1% of bovine serum without loss of production of monoclonal antibody. Adaptation of this hybridoma to growth without any serum supplement was not possible during the course of this experimental series.

Monoclonal antibodies against rat mast cells differentiate between subtypes.

Four monoclonal mouse anti rat mast cell antibodies were selected which detect an antigenic determinant occurring on connective tissue mast cells of the rat. A strong antigen density was found on peritoneal mast cells whereas pleural and mesenteric mast cells exhibit considerably smaller amounts of the antigen. It does not occur on lung mast cells and basophils, thus permitting a mast cell subtype differentiation according to the expression of a surface antigen.

[Effect of a proliferation- stimulating preparation from bovine brain on cultured calf aortic endothelial cells].

A preparation from bovine brain (HS-3) stimulates the proliferation of a calf aortic cell line (BKEz-7) in concentrations between 50-200 micrograms/ml. It is especially effective at low inoculum cell density, it economizes fetal serum and is very efficient as additive for the improvement of inadequate sera. Important questions for the practical use as the properties of the preparation with regard to durability and sterile filtration have been investigated.