Analysis of the in vitro secretory activity of human pituitary adenomas: modification of corticotropin release from adenoma tissue explant cultures by addition of a human plasma ultrafiltrate bioactive fraction.

The lack of control of tumour behaviour is manifested in different ways, depending primarily on the type of tumour. This results in numerous problems of tumour diagnosis and therapy. In the case of "benign" tumours, like pituitary adenomas, in vitro studies are often used for evaluation of the tumour. The use of tissue explant cultures of human pituitary adenomas and the comparison of the feature of cultured tumours with their behaviour in vivo showed that corticotropin is released not only from the tumours associated with Cushing's disease, but also from clinically non-functioning tumours. Hence, it was supposed that the release of corticotropin in vivo from non-secreting tumours is probably under the influence of certain neuroendocrine and/or systemic humoral factors. To test this possibility, samples of 22 tumours were cultured in plain culture medium or in the presence of the "human plasma ultrafiltrate bioactive fraction" (tentatively termed as TBP) prepared by anion-exchange chromatography. In the presence of TBP the release of corticotropin was strongly inhibited in adenomas showing relatively high spontaneous secreting activity in vitro (> 200 ng/l in 24 hours), while immunohistochemistry of these tumours indicated accumulation of corticotropin inside the cells. In contrast, TBP stimulated corticotropin release from tumours that showed relatively low basic corticotropin release (< 200 ng/l in 24 hours), with no obvious change in cellular corticotropin immunoreactivity. Such a dual activity of TBP was not observed for 8 samples of adenomas cultured in the presence of surrounding pituitary tissue, probably because TBP did not affect corticotropin secretion by the normal pituitary cells (as indicated by immunohistochemistry). From these results, it appears that TBP could be one of the humoral factors involved in the regulation of corticotropin release from pituitary adenoma tissue. Its possible involvement in the regulation of corticotropin release from normal pituitary tissue, however, is uncertain.

Gastric lesion development in normal and pylorus ligated rats after cervical vagotomy.

The main purpose of this study was to further investigate the effects of vagotomy on gastric lesion development. In contrast to the usual subdiaphragmal vagotomy, a different vagotomy at the level of the trigonum caroticum was used both alone and in combination with pylorus ligation (done immediately after vagal transection). The animals were killed 15 min, 30 min, 1 h and 6 h following vagotomy. No damaging effects of sham-vagotomy, or obvious negative effects of cervical vagotomy were noted. Prominent lesions appeared after 1 h in rats subjected to cervical vagotomy and significantly increased lesions in the early period of pylorus ligation were noted. No further aggravation in pylorus ligated rats (even an apparent amelioration at 1-h interval) and no lesions in rats with cervical vagotomy in the latter period could be explained in terms of a lack of reactivity due to exhaustion preceding fatal outcome. Consistent with this, the rats subjected to cervical vagotomy died shortly after the 6-h period.