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LACK OF RISE IN SERUM PROLACTIN FOLLOWING YTTRIUM‐90 INTERSTITIAL IRRADIATION FOR ACROMEGALY
Author(s) -
CLARK A. J. L.,
CHAHAL P.,
MASHITER K.,
JOPLIN G. F.
Publication year - 1983
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1983.tb00031.x
Subject(s) - acromegaly , medicine , endocrinology , prolactin , hypothalamus , irradiation , yttrium , pituitary gland , chemistry , hormone , growth hormone , physics , organic chemistry , nuclear physics , oxide
SUMMARY We have investigated the possibility that the increase in serum PRL levels observed in patients with acromegaly treated with external irradiation could be due to damage to the hypothalamus or portal vessels, by comparing the effects of yttrium‐90 interstitial irradiation, which is highly localised and does not normally extend to the hypothalamus, in a similar series of patients. Sixteen acromegalic patients treated by interstitial irradiation with yttrium‐90 are described; GH fell from a mean of 131 mU/1 (median 113 mU/1) to 17 mU/1 (median 8 mU/1) after one year ( P < 0·001). PRL fell in the five initially hyperprolactinaemic patients (mean fall ± SD: 39 ± 17 μg/1 at one year), but remained unchanged in the normoprolactinaemic group; PRL responsiveness to TRH was retained. Five, out of the seven normoprolactinaemic patients examined, were shown by in vitro studies of their pituitary biopsies, to have tumours that also synthesised or secreted PRL. These results are consistent with the hypothesis that the rise in PRL following external irradiation is the result of damage to the hypothalamus or portal vessels. A less likely explanation is that an overgrowth of radio‐resistant PRL‐secreting tumour cells is occurring after external irradiation, but not after yttrium‐90 implantation.