Effects of Thyrotropin-Releasing Hormone and Metoclopramide in Patients with Phenothiazine-Induced Hyperprolactinemia*

Abstract

TRH and metoclopramide tests were performed in 10 female patients with presumed phenothiazine-induced hyperprolactinemia to define the serum PRL response to these agents. Our results show that the serum PRL response to metoclopramide is blunted in most patients with phenothiazine-induced hyperprolactinemia, and the serum PRL response to TRH is exaggerated in most patients during and 3 weeks after stopping phenothiazines.

L‐Tryptophan and prolactin release: Evidence for interaction between 5‐HT1 and 5‐HT2 receptors

“…The finding that ritanserin increased the PRL response to LTP was unexpected, consequently a number of possible explanations should be considered. Several subjects exhibited increases in basal PRL levels following ritanserin and there is some evidence that elevations in basal PRL may increase the PRL response to subsequent provocative stimuli (Cowen el al., 1985;Chalmers et al, 1978;Lankford et al, 1981). In general, however, this is found with elevations in basal PRL somewhat greater than those seen here (Cowen et al, 1985;Braddock and Blake, 1981) and in addition we found no correlation between basal PRL concentration and the PRL response to LTP.…”

The autonomy of prolactin secretion in patients with prolactin producing tumor.

“…Although patients with PRLproducing tumor (PRL-noma) Show PRL responses to exogenous stimuli, such responses are less frequent compared to normal subjects (Tolis et al 1974;Boyd et al 1977;Crosignani et al 1977;Kleinberg et al 1977;Barbarino et al 1978;Lankford et al 1981). However, it is not clear whether there are some differences in PRL responsiveness among these patients as we have reported clear differences in Gi secretion in patients with acromegaly (Hanew et al 1980a).…”

Dynamic evaluation of prolactin secretion by successive TRH and metoclopramide stimulations

“…In certain circumstances these tests are of clinical importance. In phenothiazide-induced hyperpro¬ lactinaemia the Prl response to MC was blunted and that to TRH was exaggerated (Lankford et al 1981). In similar clinical conditions a blunted Prl response to TRH implies the possibility of a co¬ existing prolaetinoma.…”

“…In the evaluation of Prl secretion a single injection of thyrotrophin releas¬ ing hormone (TRH) (Jacobs et al 1971;Peillon et al 1982 (Judd et al 1976;Sowers et al 1976;Cowden et al 1979;Leroith et al 1979;Pineda et al 1979;Lankford et al 1981;Kauppila & Ylikorkala 1982) …”