Dynamics of prolactin secretion from diethylstilbestrol-induced rat prolactinoma tissue in vitro. Proc Soc Exp Biol Med 1995 Nov;210(2):150-5
Date
11/01/1995Pubmed ID
7568285DOI
10.3181/00379727-210-43934Scopus ID
2-s2.0-0028834762 (requires institutional sign-in at Scopus site) 3 CitationsAbstract
Experiments were performed to determine whether PRL secretion in the rat diethylstilbestrol (DES)-induced prolactinoma model is affected by the addition of thyrotropin-releasing hormone (TRH) and/or immunoneutralization of intrapituitary vasoactive intestinal polypeptide (VIP) in vitro. Male Fischer 344 rats were implanted with either a 10 mg DES or placebo pellet 30 days prior to obtaining the anterior pituitary glands for perifusion. The anterior pituitaries were quartered and used in three different perifusion experiments. In Experiment I, placebo-treated tissue channels were perifused for 2 baseline hr followed consecutively by a 30-min exposure to 1:100 nonimmune rabbit serum (NRS), a 30-min wash, and a final 30-min exposure to 10(-5) M TRH. Additional placebo channels were run as above except 1:100 VIP antiserum (AVIP) was substituted for NRS and AVIP was added to the TRH. In Experiment II, the same perifusion protocol was used as in Experiment I, except DES-induced tumor tissue was used instead of placebo tissue. Results from Experiment I and II reveal that AVIP significantly decreased PRL secretory rate in both DES and placebo groups. In the tumor group, both TRH alone and in the presence of AVIP significantly increased the PRL secretory rate. In Experiment III DES-induced tumor tissue channels were perifused with a similar protocol, except the concentrations of NRS and AVIP were increased to 1:10. Both NRS and AVIP significantly decreased PRL secretory rate; however, AVIP had a significantly greater effect than NRS. In this experiment, 1:10 AVIP overcame the stimulatory effect of TRH. In conclusion, AVIP decreases and TRH increases, even in the presence of AVIP, PRL release in DES-induced prolactinoma tissue in vitro. Increasing the AVIP concentration 10-fold diminished the PRL-releasing action of TRH in the tumor tissue. These data suggested that PRL secretion is not autonomous in these prolactinomas and can be affected by exogenous TRH and partial immunoneutralization of endogenous VIP.
Author List
Maas DL, Martinson DR, Erdmann MD, Wahle JS, Hagen TCMESH terms used to index this publication - Major topics in bold
AnimalsDiethylstilbestrol
Immune Sera
In Vitro Techniques
Male
Pituitary Gland, Anterior
Pituitary Neoplasms
Placebos
Prolactin
Prolactinoma
Rabbits
Radioimmunoassay
Rats
Rats, Inbred F344
Thyrotropin-Releasing Hormone
Vasoactive Intestinal Peptide
