Effect of Reserpine on Pituitary Prolactin Content and Its Hypothalamic Site of Action in the Rabbit

Kanematsu, Shigeto; Hilliard, Jessamine; Sawyer, Charles H.

doi:10.1530/acta.0.0440467

Cited by 27 publications

(5 citation statements)

References 7 publications

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“…Initial clues that this might not be the case came from observations that drugs such as reserpine, which depletes endogenous catecholamines, induced pseudopregnancy in rats ( Barraclough & Sawyer 1959 ), indicative of elevated prolactin. It was assumed, however, that the functional role of catecholamines were as neurotransmitters acting in the hypothalamus to regulate the release of a hypothalamic hormone ( Kanematsu et al . 1963 ).…”

Section: Neuroendocrine Control Of Prolactin Secretionmentioning

confidence: 99%

60 YEARS OF NEUROENDOCRINOLOGY: The hypothalamo-prolactin axis

Grattan¹

2015

Journal of Endocrinology

283

203

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The hypothalamic control of prolactin secretion is different from other anterior pituitary hormones, in that it is predominantly inhibitory, by means of dopamine from the tuberoinfundibular dopamine neurons. In addition, prolactin does not have an endocrine target tissue, and therefore lacks the classical feedback pathway to regulate its secretion. Instead, it is regulated by short loop feedback, whereby prolactin itself acts in the brain to stimulate production of dopamine and thereby inhibit its own secretion. Finally, despite its relatively simple name, prolactin has a broad range of functions in the body, in addition to its defining role in promoting lactation. As such, the hypothalamo-prolactin axis has many characteristics that are quite distinct from other hypothalamo-pituitary systems. This review will provide a brief overview of our current understanding of the neuroendocrine control of prolactin secretion, in particular focusing on the plasticity evident in this system, which keeps prolactin secretion at low levels most of the time, but enables extended periods of hyperprolactinemia when necessary for lactation. Key prolactin functions beyond milk production will be discussed, particularly focusing on the role of prolactin in inducing adaptive responses in multiple different systems to facilitate lactation, and the consequences if prolactin action is impaired. A feature of this pleiotropic activity is that functions that may be adaptive in the lactating state might be maladaptive if prolactin levels are elevated inappropriately. Overall, my goal is to give a flavour of both the history and current state of the field of prolactin neuroendocrinology, and identify some exciting new areas of research development.

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Section: Neuroendocrine Control Of Prolactin Secretionmentioning

confidence: 99%

60 YEARS OF NEUROENDOCRINOLOGY: The hypothalamo-prolactin axis

Grattan¹

2015

Journal of Endocrinology

283

203

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“…Thus, it can be assumed that reserpine has no direct action on the adrenal gland but does act as a stimulator for ACTH. Reserpine also stimulates prolactin (21,22), and it was reported that human prolactin rather than ACTH stimulated estrogen production, especially estradiol, by feminizing adrenal neoplastic cells (23). This finding indicates,…”

Section: Discussionmentioning

confidence: 88%

Effect of acth on adrenal estrogens.

Higashi

Aizawa

1980

Jpn.J.Pharmacol

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Abstract-Tissue levels of rat adrenal estrogens during the estrous cycle were determined by radioimmunoassay, and effect of ACTH on the adrenal estrogen levels was examined. The levels of estrone and estradiol in proestrus were 2.75+0.61 pg/mg tissue and 1.0± 0.19 pg/mg tissue (mean i SE), respectively. The higher level of estrone but not of estradiol was inclined to appear in proestrus rather than in other phases. Injection of 250 IU/kg of a1-24-ACTH significantly increased the estrone level at 15 and 30 min, and estradiol at 15 min. Administration of reserpine, which was used as the ACTH releaser, produced an increase in the estrone level but did not change the estradiol level. While dexamethasone injection decreased the estrone level significantly at 8 hours after the treatment, the level of estradiol remained unchanged. Hypophysectomy produced a considerable decrease in both steroid levels, particularly estrone. These results indicate that the major estrogen in the rat adrenal gland is estrone and that the level is regulated by hypophyseal ACTH.It has been reported that the plasma or urinary estrogen level remained unchanged in ovariectomized and postmenopausal women, and also that the level increased in subjects with adrenocortical tumor or hyperplasia. In addition, it has been reported that estrogens were produced in adrenal glands besides the ovary, on the basis of the increase of plasma or urinary estrogens with ACTH treatment and decreases seen with dexamethasone treatment (1-5).However, a distinct function of the rat adrenal estrogens has not been clarified. Our study was carried out to determine the level of estrogens in rat adrenal gland during estrous cycle.The interaction between ACTH and adrenal estrogens was also examined using reserpine as the ACTH releaser and both dexamethasone injection and hypophysectomy as ACTH depressor, in order to provide more information on the rat species. MATERIALS AND METHODSAdult, female, Wistar rats weighing 200 g, were housed in a room with controlled temperature (24+1°C) and light (from 6:30 a.m. to 6:30 p.m.). Food and water were given freely. Rats with 3-4 successive regular 4-day estrous cycle were used, and were decapitated at 11:00 a.m., in all the experiments. Rats were used for 48 hr after hypophy sectomy by the external auditory canal method, under ether anesthesia. There were 10 rats per group in all the experiments.After a1-24-ACTH (Daiichi Pharmaceutical Co. Ltd.) had been given s.c., in a dose of 250 IU/kg, dissolved in physiological saline, the rats were sacrificed at 15, 30, and 60 min with minimum disturbance. Dexamethasone phosphate (Sankyo Co. Ltd.) was also given s.c. in a dose of 100 ucg/kg, and the rats were sacrificed at 2, 4, 8, and 24 hr after adminis

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“…The injection of reserpine induces pseudopregnancy in rats (Barraclough & Sawyer, 1959) and a lactogenic effect has been reported in rabbits (Meites, 1957) and rats (Benson, 1958). Furthermore, after reserpine treatment a drop in pituitary prolactin content in rats (Moon & Turner, 1959) and in ovariectomized, oestrogenprimed rabbits (Kanematsu, Hilliard & Sawyer, 1963) has been described. These facts indicate that a similar mechanism may be involved in the control of secretion of MSH and prolactin.…”

Section: Discussionmentioning

confidence: 94%

Influence of Reserpine on the Pituitary Content of Melanocyte-Stimulating Hormone and on Hypothalamic Factors Which Affect Its Release

Taleisnik¹

1968

Journal of Endocrinology

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SUMMARY The melanocyte-stimulating hormone (MSH) content of whole toad pituitary glands decreased upon treatment with reserpine. With daily injections the values remained low for 1 week but regained normal levels after 2 weeks in spite of an increased secretion of MSH as indicated by darkening of the skin. In rats a drop in pituitary MSH content also occurred after reserpine injection but normal values were found after 7 and 14 days of treatment. MSH-releasing factor found in stalk-median eminence tissue of normal male rats was not present in the reserpine-injected animals, but after 7 days of treatment an increase in MSH-release-inhibiting factor (MSH-R-IF) was demonstrated. MSH-R-IF was also found to have increased in female castrated rats after 2 days of treatment with reserpine. It is concluded that reserpine permits the secretion of pituitary MSH by blocking the release of MSH-R-IF, which accumulates in the hypothalamic neurones.

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Effect of Reserpine on Pituitary Prolactin Content and Its Hypothalamic Site of Action in the Rabbit

Cited by 27 publications

References 7 publications

60 YEARS OF NEUROENDOCRINOLOGY: The hypothalamo-prolactin axis

60 YEARS OF NEUROENDOCRINOLOGY: The hypothalamo-prolactin axis

Effect of acth on adrenal estrogens.

Influence of Reserpine on the Pituitary Content of Melanocyte-Stimulating Hormone and on Hypothalamic Factors Which Affect Its Release

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