Estrogen inhibition of dopamine release into hypophysial portal blood

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

Research output: Contribution to journalArticle

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Abstract

The hypothesis that 17β estradiol suppresses dopamine secretion into hypophysial portal bood was tested. Portal plasma concentrations of dopamine were significantly lower in proestrous rats (1.0 ± 0.1 ng/ml; mean ± SE) than in estrous rats (1.9 ± 0.38 ng/ml). To deplete the animal of endogenous steroid hormones, proestrous rats were adrenalectomized (Adx) and ovariectomized (Ovx). Twenty four hours later, hypophysial portal blood was collected for 60 min, and the plasma from this blood was analyzed for dopamine. Arterial plasma from these rats was assayed for 17β estradiol and progesterone. The concentrations of dopamine in the portal plasma of sham operated rats and bilaterally Adx-Ovx rats were similar to those in estrous animals. The concentration of dopamine in portal plasma of Adx-Ovx rats injected 24 h earlier with 50 μg 17β estradiol was 1.0 ± 0.31 ng/ml, which was comparable to that in proestrous animals but less than that in the estrous rats. The concentrations of 17β estradiol in arterial plasma were as follows: 54 ± 8.3 pg/ml in proestrous rats, 40 ± 2.9 pg/ml in estrous rats, 10 ± 1.3 pg/ml in Adx-Ovx rats, and 96 ± 17.3 pg/ml in Adx-Ovx rats injected with 50 μg 17β estradiol. Twenty four hours after injection of 25 μg 17β estradiol into Adx-Ovx rats, the plasma 17β estradiol levels were 51 ± 7.4 pg/ml, and the dopamine concentrations in portal plasma were 1.9 ± 0.57 ng/ml. It is concluded that an acute effect of 17β estradiol is suppression of hypothalamic secretion of dopamine into hypophysial portal blood.

Original languageEnglish (US)
Pages (from-to)419-422
Number of pages4
JournalEndocrinology
Volume104
Issue number2
StatePublished - 1979

Fingerprint

Dopamine
Estrogens
Estradiol
Progesterone
Steroids
Hormones
Injections

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Cite this

Cramer, O. M., Parker, C. R., & Porter, J. C. (1979). Estrogen inhibition of dopamine release into hypophysial portal blood. Endocrinology, 104(2), 419-422.

Estrogen inhibition of dopamine release into hypophysial portal blood. / Cramer, O. M.; Parker, C. R.; Porter, J. C.

In: Endocrinology, Vol. 104, No. 2, 1979, p. 419-422.

Research output: Contribution to journalArticle

Cramer, OM, Parker, CR & Porter, JC 1979, 'Estrogen inhibition of dopamine release into hypophysial portal blood', Endocrinology, vol. 104, no. 2, pp. 419-422.
Cramer OM, Parker CR, Porter JC. Estrogen inhibition of dopamine release into hypophysial portal blood. Endocrinology. 1979;104(2):419-422.
Cramer, O. M. ; Parker, C. R. ; Porter, J. C. / Estrogen inhibition of dopamine release into hypophysial portal blood. In: Endocrinology. 1979 ; Vol. 104, No. 2. pp. 419-422.
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