Effects of basic fibroblastic growth factor on the function and proliferation of human clinically non-functional pituitary adenomas which secreted glycoprotein hormones in vitro.

The effects of human recombinant basic fibroblastic growth factor (bFGF) on the secretion, viability, proliferation, attachment and morphology of ten dispersed human clinically non-functional (NF) adenomas were examined in vitro. Four clinically NF adenomas secreting FSH and/or LH in vitro were unaffected by 10 nM bFGF over a 4-h period. Over 4 days 10 nM bFGF stimulated LH secretion (66% and 72%, P < 0.01) from two out of seven clinically NF adenomas secreting LH, whilst FSH (three tumours) and alpha-subunit secretion (three tumours) were unaffected. One adenoma co-secreting LH and alpha-subunit and one secreting LH alone were studied over 21 days; LH secretion fell progressively, but the decline was significantly less (P < 0.05) with bFGF (10 nM) treatment after 14 and 21 days in both adenomas, whilst the fall in alpha-subunit secretion was unaffected by bFGF treatment. A 24-h GnRH test performed at the start and end of the 21-day period in one of these tumours showed an increase in both basal and stimulated LH secretion in the bFGF-treated group over control (124%, P < 0.001). There was no effect of bFGF (10 nM) on viability, S-phase proliferation, attachment or morphology of adenoma cells over a 4-day period. These results suggest that bFGF has a role in tumorous LH secretion from these adenomas, but is not mitogenic (at least over 4 days) and is without effect on other parameters of in vitro differentiated function.