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Heterogeneity of pituitary adenoma cell subpopulations from acromegalic patients obtained by Percoll density gradient
L J Hofland1, P M van Koetsveld, T M Verleun
1Department of Medicine, Erasmus University, The Netherlands.
Unlabelled:
Pituitary adenoma cells from 6 acromegalic patients were separated on continuous Percoll density gradients according to differences in their density. Two adenomas produced GH only in culture, the other 4 adenomas produced either GH and PRL (one adenoma) or GH and alpha-subunit (one adenoma) or GH, PRL and alpha-subunit (2 adenomas). The cell subpopulations obtained by this technique differed in the amount of hormone production per 10(5) cells: GH release decreased from the low density fractions to the higher density fractions in 5 of 6 adenomas. Intracellular GH levels completely followed this profile. In the mixed GH/alpha-subunit adenomas the alpha-subunit profile completely paralleled the GH profile, whereas in the mixed GH/PRL adenomas the PRL profile showed a pattern different from that of GH (and alpha-subunit). In neither of the adenomas did we find any differences between the subpopulations with respect to the responsiveness of GH, PRL or alpha-subunit release to GHRH, TRH and the somatostatin analogue SMS 201-995.
Conclusions:
1. Within pituitary adenomas from acromegalic patients heterogeneity exists with respect to hormone production per cell. 2. The cell subpopulations obtained by density gradient centrifugation are not different in their responsiveness to SMS 201-995, GHRH or TRH. 3. Because GH and alpha-subunit release by the fractions from the mixed GH/alpha-subunit secreting adenomas were completely parallel, further evidence for co-release of GH and alpha-subunit by the same tumoural cells is provided.