open access

Vol 63, No 2 (2012)
Original papers
Published online: 2012-04-27
Submitted: 2013-02-15
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Effects of nitric oxide synthase inhibition on diethylstilbestrol-induced hyperprolactinaemia and pituitary tumourigenesis in rats

Marek Pawlikowski, Hanna Pisarek, Jolanta Fryczak, Henryk Stępień
Endokrynologia Polska 2012;63(2):115-118.

open access

Vol 63, No 2 (2012)
Original papers
Published online: 2012-04-27
Submitted: 2013-02-15

Abstract

Introduction: The overexpression of nitric oxide synthase (NOS) has been found in tumours, including pituitary adenomas. It has also been found that NOS is overexpressed in human spontaneous pituitary adenomas. The question arises whether NOS and its product, nitric oxide (NO), are involved in pituitary tumourigenesis. To investigate this question, in the present paper we examine the effects of NOS inhibition on the development of diethylstilbestrol (DES)-induced prolactin–secreting pituitary tumours in rats.
Material and methods:
Thirty male Fisher 344 rats, four weeks old, were submitted to subcutaneous implantation of a silastic capsule containing DES (10 mg/capsule) or of an empty capsule. Six weeks after implantation, some of the DES-treated animals received a NOS inhibitor, N-nitro-l-arginine methyl ester (NAME), 1 mg/mL, in their drinking water, for the subsequent 14 days. Eight weeks after the implantation, all the animals were sacrificed, their pituitaries were weighed, and samples of heart blood were collected for prolactin (PRL) and vascular endothelial growth factor (VEGF) measurements.
Results:
It was found that DES implantation significantly increased pituitary mass, as well as PRL and VEGF concentrations in blood serum. On the other hand, the administration of NAME did not affect significantly either VEGF concentration or pituitary mass. On the other hand, it did induce a further increase in PRL levels.
Conclusions: These findings indicate that NO is involved in oestrogen-induced hyperprolactinaemia, but does not play a crucial role in oestrogen-induced pituitary tumourigenesis. (Pol J Endocrinol 2012; 63 (2): 115–118)

Abstract

Introduction: The overexpression of nitric oxide synthase (NOS) has been found in tumours, including pituitary adenomas. It has also been found that NOS is overexpressed in human spontaneous pituitary adenomas. The question arises whether NOS and its product, nitric oxide (NO), are involved in pituitary tumourigenesis. To investigate this question, in the present paper we examine the effects of NOS inhibition on the development of diethylstilbestrol (DES)-induced prolactin–secreting pituitary tumours in rats.
Material and methods:
Thirty male Fisher 344 rats, four weeks old, were submitted to subcutaneous implantation of a silastic capsule containing DES (10 mg/capsule) or of an empty capsule. Six weeks after implantation, some of the DES-treated animals received a NOS inhibitor, N-nitro-l-arginine methyl ester (NAME), 1 mg/mL, in their drinking water, for the subsequent 14 days. Eight weeks after the implantation, all the animals were sacrificed, their pituitaries were weighed, and samples of heart blood were collected for prolactin (PRL) and vascular endothelial growth factor (VEGF) measurements.
Results:
It was found that DES implantation significantly increased pituitary mass, as well as PRL and VEGF concentrations in blood serum. On the other hand, the administration of NAME did not affect significantly either VEGF concentration or pituitary mass. On the other hand, it did induce a further increase in PRL levels.
Conclusions: These findings indicate that NO is involved in oestrogen-induced hyperprolactinaemia, but does not play a crucial role in oestrogen-induced pituitary tumourigenesis. (Pol J Endocrinol 2012; 63 (2): 115–118)
Get Citation

Keywords

nitric oxide; prolactin; VEGF; oestrogen-induced pituitary tumour

About this article
Title

Effects of nitric oxide synthase inhibition on diethylstilbestrol-induced hyperprolactinaemia and pituitary tumourigenesis in rats

Journal

Endokrynologia Polska

Issue

Vol 63, No 2 (2012)

Pages

115-118

Published online

2012-04-27

Bibliographic record

Endokrynologia Polska 2012;63(2):115-118.

Keywords

nitric oxide
prolactin
VEGF
oestrogen-induced pituitary tumour

Authors

Marek Pawlikowski
Hanna Pisarek
Jolanta Fryczak
Henryk Stępień

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