[The behavior of the human hypophyseal tumor in vitro. An analysis of tumor biology in 51 consecutive operated cases].

The in vitro behaviour of 51 consecutively operated cases was analyzed. Clinically, 18 tumours secreted GH, 15 had a concomitant secretion of GH and PRL, 10 secreted PRL, 3 secreted ACTH and 5 were clinically regarded as non-secreting. When using the organ culture technique with tissue in organotypic differentiation, hormone secretion (GH, PRL and ACTH) occurred during the whole 6 week period. Hormone secretion was correlated to weight in 74 specimens. A secretion rate of between 5000 and 55 000 pmol/mg wet weight/24 h of GH and 2500-7800 micrograms/mg wet weight/24 h of PRL occurred. Pituitary tumours clinically regarded as non-secreting showed a low secretion of GH (6-100 pmol/24 h/culture dish) and PRL (6,3-40 micrograms/24 h/culture dish). However, the hormone secretion rate in explants from these tumours rapidly decreased with time in vitro. No spontaneous degeneration of GH or PRL occurred during 2 h in vitro when the explant had been removed. In vivo irradiated tumours revealed a low secretion rate of GH, PRL and ACTH, respectively, when explanted to organ culture.