Influence of Levodopa on Serum Levels of Anterior Pituitary Hormones in Man

1972 ◽  
Vol 10 (5) ◽  
pp. 309-315 ◽  
Author(s):  
G. Boden ◽  
L.E. Lundy ◽  
O.E. Owen
Keyword(s):  
Anterior Pituitary ◽  
Serum Levels ◽  
Pituitary Hormones ◽  
Anterior Pituitary Hormones

Effects of exogenous monoiodotyrosine on the serum levels of anterior pituitary hormones

1991 ◽  
Vol 124 (3) ◽  
pp. 251-257
Author(s):  
Stanley A. Tan ◽  
John E. Lewis ◽  
Lee S. Berk ◽  
R. Bruce Wilcox
Keyword(s):  
Tyrosine Hydroxylase ◽  
Anterior Pituitary ◽  
Fold Increase ◽  
Serum Levels ◽  
Pituitary Hormones ◽  
Dopamine Synthesis ◽  
Dopamine Infusion ◽  
Synthesis Inhibition ◽  
Anterior Pituitary Hormones

Abstract. Monoiodotyrosine is a tyrosine hydroxylase inhibitor. Ingestion of one gram monoiodotyrosine caused a 10000-fold increase of serum monoiodotyrosine from basal levels of 0.69±0.20 nmol/l to a peak of 10.6±1.7 μmol/l in women and 7.1±2.3 μmol/l in men 30 min later, and the t½ was 45 min. Monoiodotyrosine stimulated PRL to a peak of 170±51 μg/l in women and 90±6 μg/l in men 30 min after the monoiodotyrosine peak, or 60 min after the ingestion. Other anterior pituitary hormones were unchanged. Dopamine infusion or L-dopa pretreatment attenuated the monoiodotyrosine effect. TRH exaggerated the PRL peak, and chlorpromazine did not increase but prolonged the hyperprolactinemia. These results suggest that dopamine synthesis inhibition may be the mechanism of PRL stimulation.

scholarly journals Investigation of the serum levels of anterior pituitary hormones in male children with autism

2011 ◽  
Vol 2 (1) ◽  
pp. 16 ◽  
Author(s):  
Keiko Iwata ◽  
Hideo Matsuzaki ◽  
Taishi Miyachi ◽  
Chie Shimmura ◽  
Shiro Suda ◽  
...  
Keyword(s):  
Anterior Pituitary ◽  
Children With Autism ◽  
Serum Levels ◽  
Pituitary Hormones ◽  
Anterior Pituitary Hormones

Ultrastructural morphology of nontumorous lactotrophs in human pituitaries exposed to high prolactin levels

1987 ◽  
Vol 45 ◽  
pp. 896-897
Author(s):  
S. Jalalah ◽  
K. Kovacs ◽  
E. Horvath
Keyword(s):  
Anterior Pituitary ◽  
Secretory Activity ◽  
Pituitary Hormones ◽  
Feedback Mechanism ◽  
Endocrine Activity ◽  
Hormone Synthesis ◽  
Anterior Pituitary Hormones ◽  
Negative Feedback Mechanism ◽  
Ultrastructural Morphology ◽  
Transmission Electron

Lactotrophs, as many other endocrine cells, change their morphology in response to factors influencing their secretory activity. Secretion of prolactin (PRL) from lactotrophs, like that of other anterior pituitary hormones, is under the control of the hypothalamus. Unlike most anterior pituitary hormones, PRL has no apparent target gland which could modulate the endocrine activity of lactotrophs. It is generally agreed that PRL regulates its own release from lactotrophs via the short loop negative feedback mechanism exerted at the level of the hypothalamus or the pituitary. Accordingly, ultrastructural morphology of lactotrophs is not constant; it is changing in response to high PRL levels showing signs of suppressed hormone synthesis and secretion.By transmission electron microscopy and morphometry, we have studied the morphology of lactotrophs in nontumorous (NT) portions of 7 human pituitaries containing PRL-secreting adenoma; these lactotrophs were exposed to abnormally high PRL levels.

scholarly journals Estrogen mediates sex differences in preoptic neuropeptide and pituitary hormone production in medaka

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Junpei Yamashita ◽  
Yuji Nishiike ◽  
Thomas Fleming ◽  
Daichi Kayo ◽  
Kataaki Okubo
Keyword(s):  
Anterior Pituitary ◽  
Pituitary Hormones ◽  
Pituitary Hormone ◽  
Sexually Dimorphic ◽  
Hormone Production ◽  
Anterior Pituitary Hormones ◽  
Vertebrate Brain ◽  
Pituitary Adenylate Cyclase ◽  
Evolutionarily Conserved ◽  
Sexually Dimorphic Expression

AbstractThe preoptic area (POA) is one of the most evolutionarily conserved regions of the vertebrate brain and contains subsets of neuropeptide-expressing neurons. Here we found in the teleost medaka that two neuropeptides belonging to the secretin family, pituitary adenylate cyclase-activating polypeptide (Pacap) and vasoactive intestinal peptide (Vip), exhibit opposite patterns of sexually dimorphic expression in the same population of POA neurons that project to the anterior pituitary: Pacap is male-biased, whereas Vip is female-biased. Estrogen secreted by the ovary in adulthood was found to attenuate Pacap expression and, conversely, stimulate Vip expression in the female POA, thereby establishing and maintaining their opposite sexual dimorphism. Pituitary organ culture experiments demonstrated that both Pacap and Vip can markedly alter the expression of various anterior pituitary hormones. Collectively, these findings show that males and females use alternative preoptic neuropeptides to regulate anterior pituitary hormones as a result of their different estrogen milieu.

Anterior Pituitary Hormones

Hormones ◽  
1997 ◽  
pp. 133-168
Author(s):  
Anthony W. Norman ◽  
Gerald Litwack
Keyword(s):  
Anterior Pituitary ◽  
Pituitary Hormones ◽  
Anterior Pituitary Hormones

Vasopressin as a neuroendocrine regulator of anterior pituitary hormone secretion

1993 ◽  
Vol 129 (6) ◽  
pp. 489-496 ◽  
Author(s):  
Andreas Kjær
Keyword(s):  
Arginine Vasopressin ◽  
Mode Of Action ◽  
Anterior Pituitary ◽  
Hormone Secretion ◽  
Pituitary Hormones ◽  
Pituitary Hormone ◽  
Anterior Pituitary Hormones ◽  
Anterior Pituitary Hormone

Secretion of the anterior pituitary hormones adrenocorticotropin (ACTH), β-endorphin and prolactin (PRL) is complex and involves a variety of factors. This review focuses on the involvement of arginine-vasopressin (AVP) in neuroendocrine regulation of these anterior pituitary hormones with special reference to receptor involvement, mode of action and origin of AVP. Arginine-vasopressin may act via at least two types of receptors: V1− and V2−receptors, where the pituitary V1−receptor is designated V1b. The mode of action of AVP may be mediating, i.e. anterior pituitary hormone secretion is transmitted via release of AVP, or the mode of action may be permissive, i.e. the presence of AVP at a low and constant level is required for anterior pituitary hormones to be stimulated. Under in vivo conditions, the AVP-induced release of ACTH and β-endorphin is mainly mediated via activation of hypothalamic V1− receptors, which subsequently leads to the release of corticotropin-releasing hormone. Under in vitro conditions, the AVP-stimulated release of ACTH and β-endorphin is mediated via pituitary V1b− receptors. The mode of action of AVP in the ACTH and β-endorphin response to stress and to histamine, which is involved in stress-induced secretion of anterior pituitary hormones, is mediating (utilizing V1− receptors) as well as permissive (utilizing mainly V1− but also V2−receptors). The AVP-induced release of PRL under in vivo conditions is conveyed mainly via activation of V1−receptors but V2−receptors and probably additional receptor(s) may also play a role. In stress- and histamine induced PRL secretion the role of AVP is both mediating (utilizing V1 −receptors) and permissive (utilizing both V1− and V2− receptors). Arginine-vasopressin may be a candidate for the PRL-releasing factor recently identified in the posterior pituitary gland. Arginine-vasopressin of both magno- and parvocellular origin may be involved in the regulation of anterior pituitary hormone secretion and may reach the corticotrophs and the lactotrophs via three main routes: the peripheral circulation, the long pituitary portal vessels or the short pituitary portal vessels.

Effect of the Dopamine Agonist, Lergotrile Mesylate, on Circulating Anterior Pituitary Hormones in Man*

1978 ◽  
Vol 47 (2) ◽  
pp. 372-378 ◽  
Author(s):  
M. O. THORNER ◽  
SUSAN M. RYAN ◽  
J. A. H. WASS ◽  
ANN JONES ◽  
P. BOULOUX ◽  
...  
Keyword(s):  
Dopamine Agonist ◽  
Anterior Pituitary ◽  
Pituitary Hormones ◽  
Anterior Pituitary Hormones
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