Recent reports indicate that
fibroblast growth factors known to be present in the pituitary in high levels regulate the action of
growth hormone and
prolactin. New data also suggest a regulatory role in the pituitary for other
growth factors, such as
epidermal growth factor (
EGF) and
transforming growth factor-alpha (
TGF-alpha). Since in most systems cooperation of several
growth factors is required for their optimal function, we sought to demonstrate the presence of certain
growth factors in the pituitary.
Acid ethanol extracts from approximately 50 autopsy-derived human pituitaries were subjected to molecular sieve chromatography and were tested for
growth factors. Low molecular weight
protein (10 micrograms) eluted from the molecular sieve column contained 10-20 ng material binding to the
EGF/
TGF-alpha receptor as determined by the
EGF/
TGF alpha radioreceptor binding assay which represents 11 ng
EGF/
TGF alpha per pituitary. By Western blotting we found
EGF but could not document the presence of
TGF-alpha in this material. Radioimmunoassay for
insulin-like growth factor I detected 0.4-0.8 ng
insulin-like growth factor-I/100 micrograms extract.
TGF-beta eluted between 14,000 and 20,000 M(r) at levels of 3-4 ng/pituitary. Its ability to inhibit growth of CC164 mink lung cells was abolished by antibody to
TGF-beta 1 but not by antibody raised against
TGF-beta 2. The detection of
platelet derived growth factor was equivocal and not fully reproducible. We have partially purified
TGFe from the pituitary; it stimulated soft
agar growth of
carcinoma SW-13 cells, and it followed an elution pattern identical to bovine kidney
TGFe on molecular sieve column and high pressure liquid and high performance electrophoretic chromatography. Our data show that in addition to
fibroblast growth factors, the human pituitary contains other
growth factors, such as
EGF/
TGF-alpha,
TGF-beta,
insulin-like growth factor I, and
TGFe.