Secretion of dopamine into hypophysial portal blood by rats bearing prolactin-secreting tumors or ectopic pituitary glands

O. M. Cramer, C. R. Parker, J. C. Porter

Research output: Contribution to journalArticle

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Abstract

Catecholamines were quantified in hypophysial portal plasma obtained from cycling diestrous rats and from noncycling diestrous rats with hyperprolactinemia due to PRL-secreting pituitary explants or a PRL-secreting pituitary tumor. In rats bearing PRL-secreting tumors, the plasma concentration of PRL was 4450 ± 938 ng/ml (mean ± SE), whereas in cycling diestrous animals the plasma level of PRL was 16 ± 2.2 ng/ml. The concentration of dopamine in hypophysial portal plasma of tumor-bearing rats (2.0 ± 0.3 ng/ml) was significantly greater (P < 0.05) than that in diestrous rats (1.1 ± 0.2 ng/ml). The anterior pituitary content of PRL was 18 ± 1.5 μg in cycling diestrous animals and 9 ± 0.8 μg in tumor-bearing rats. The adrenals from tumor-bearing animals were much heavier (155 ± 14 mg) than those from cycling diestrous rats (58 ± 1.2 mg). The concentration of dopamine in portal plasma from tumor-bearing adrenalectomized rats was 2.0 ± 0.5 ng/ml, similar to that in portal plasma from tumor-bearing intact animals. The arterial plasma concentration of PRL in rats bearing four anterior pituitary explants maintained under the renal capsule was 178 ± 20 ng/ml. In these same animals, the pituitary content of PRL was 11 ± 1.6 μg, which was significantly less (P<0.01) than that in cycling diestrous animals (19 ± 1.9 μg). The dopamine concentration in portal plasma from cycling diestrous rats was 1.3 ± 0.23 ng/ml and was 1.3 ± 0.36 ng/ml in the rats bearing ectopic pituitary glands. It is concluded that agents secreted by the tumor, possibly PRL and/or an ACTH-like substance, can lead to an increased secretion of dopamine by the hypothalamus.

Original languageEnglish (US)
Pages (from-to)636-638
Number of pages3
JournalEndocrinology
Volume105
Issue number3
StatePublished - 1979

Fingerprint

Pituitary Gland
Prolactin
Dopamine
Neoplasms
Hyperprolactinemia
Pituitary Neoplasms
Adrenocorticotropic Hormone
Hypothalamus
Catecholamines
Capsules
Kidney

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Cite this

Secretion of dopamine into hypophysial portal blood by rats bearing prolactin-secreting tumors or ectopic pituitary glands. / Cramer, O. M.; Parker, C. R.; Porter, J. C.

In: Endocrinology, Vol. 105, No. 3, 1979, p. 636-638.

Research output: Contribution to journalArticle

Cramer, O. M. ; Parker, C. R. ; Porter, J. C. / Secretion of dopamine into hypophysial portal blood by rats bearing prolactin-secreting tumors or ectopic pituitary glands. In: Endocrinology. 1979 ; Vol. 105, No. 3. pp. 636-638.
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