Effect of insulin-like growth factors on human foetal, adult normal and tumour pituitary function in tissue culture.
To determine the direct effects of insulin-like growth factors (IGFs) on hormone release by the human pituitary gland, human foetal, adult normal and tumour pituitary tissues were maintained in culture for 2 to 4 weeks and tested with acute (3 h) exposures to different preparations of IGF peptides. Adult normal pituitaries and adenomas were tested with a semipurified preparation of IGFs, free of immunoreactive insulin, containing IGF-I and IGF-II in a ratio of approximately 1:4. Human foetal pituitaries were tested with the semipurified IGFs as well as more purified preparations of IGF-I and IGF-II. Culture media were assayed for hGH, hPrl, hACTH and hLH using specific radioimmunoassays. Both foetal (n = 16 (No. of pituitaries), 33 (No. of observations] and normal adult (n = 3, 16) human pituitaries cultures responded to the semipurified IGFs (2-25 ngEq/ml for foetal and 2-4 ngEq/ml for adult pituitaries) with a significant decrease in hGH release compared to basal (P less than 0.01) whereas the GH-secreting pituitary tumours showed no effect when tested with from 2 to 25 ngEq/ml (n = 8, 129, NS). The effect of IGFs on human foetal somatotrope activity was dose-related for both the semipurified IGFs (2-25 ngEq/ml, n = 16, 33) and IGF-I or IGF-II (10-100 ng/ml; n = 3, 18).(ABSTRACT TRUNCATED AT 250 WORDS)
D000236:Adenoma / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000328:Adult; D000367:Age Factors; D003470:Culture Media; D046508:Culture Techniques; D005260:Female; D013006:Growth Hormone / Q000378:metabolism; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010902:Pituitary Gland / Q000187:drug effects* / Q000196:embryology / Q000378:metabolism; D010911:Pituitary Neoplasms / Q000378:metabolism; D011388:Prolactin / Q000378:metabolism; D011863:Radioimmunoassay; D013002:Somatomedins / Q000494:pharmacology*
D003470:Culture Media; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D000324:Adrenocorticotropic Hormone; D011388:Prolactin; D007986:Luteinizing Hormone; D013006:Growth Hormone