scholarly journals Autocrine and Paracrine Regulation of Prolactin Secretion by Prolactin Variants and by Hypothalamic Hormones

Prolactin ◽  
10.5772/51681 ◽  
2013 ◽  
Author(s):  
Flavio Mena ◽  
Nilda Navarro ◽  
Alejandra Castill
Keyword(s):  
Prolactin Secretion ◽  
Paracrine Regulation ◽  
Hypothalamic Hormones

SPECIAL PROBLEMS IN TOXICITY TESTING OF LONG ACTING DEPOT CONTRACEPTIVES

1974 ◽  
Vol 77 (1_Suppla) ◽  
pp. S315-S354 ◽  
Author(s):  
F. Neumann ◽  
R. von Berswordt-Wallrabe ◽  
W. Elger ◽  
K.-J. Gräf ◽  
S. H. Hasan ◽  
...  
Keyword(s):  
Biological Effects ◽  
Histological Finding ◽  
Toxicity Testing ◽  
Prolactin Secretion ◽  
List Type ◽  
Human Species ◽  
Prolactin Plasma Level ◽  
Human Use ◽  
Long Acting ◽  
Reproductive Processes

ABSTRACT Two types of so-called "depot contraceptives", long-acting steroids which are of interest for human use, were studied in animals. Norethisterone oenanthate, mainly gestagenic in the human and other species, turned out to be predominantly oestrogenic in rats. This oestrogenicity caused indirectly, via an enhanced hypophysial prolactin secretion, the well-known hypophysial and mammary tumours in rats. Another synthetic gestagen, 4,6-dichloro- 17- acetoxy- 16α-methyl-4,6-pregnadiene-3,20-dione, which might be considered in its biological actions similar to preparations containing chlormadinone acetate or medroxy-progesterone acetate, induced no signs of oestrogenicity in dogs. It is surmised that its gestagenic influence indirectly, and probaby, via an enhanced hypophysial prolactin secretion caused "mammary nodules" in this "non-rodent" species. These studies have born out mainly two facts: A synthetic steroid, norethisterone oenanthate, exerted different biological effects in different species: it was a gestagen in the rabbit, whereas in rats, its predominant influence was oestrogenic. The hypophysial prolactin secretion was enhanced in various species by different mechanisms: in rats, the oestrogenicity caused an increased prolactin plasma level, whereas in dogs, a gestagen with obviously no inherent oestrogenicity, 4,6-dichloro-17-acetoxy-16α-methyl-4,6-pregnadiene-3,20-dione, converted the histological appearance of the anterior pituitary into a condition with a greatly increased number of eosinophils. This histological finding was interpreted as an indicator for a hypersecretion of prolactin. Hence, animal work with "gestagens" has only limited predictive value with respect to their possible effects in the human species. Therefore, inflexible recommendations are not helpful in solving the safety problem of long-acting steroids which affect primarily reproductive processes.

Modulation of prolactin secretion by contraceptive progestins in cultured rat pituitary cells in vitro

1988 ◽  
Vol 117 (4_Suppl) ◽  
pp. S188-S189
Author(s):  
L. KIESEL ◽  
T. RABE ◽  
D. SCHOLZ ◽  
V. KIRSCHNER ◽  
B. RUNNEBAUM
Keyword(s):  
Prolactin Secretion ◽  
Pituitary Cells ◽  
Rat Pituitary ◽  
Rat Pituitary Cells

Melatonin Modulates Lactation by Regulating Prolactin Secretion Via Tuberoinfundibular Dopaminergic Neurons in the Hypothalamus- Pituitary System

2020 ◽  
Vol 21 (8) ◽  
pp. 744-750 ◽  
Author(s):  
Hongyang Li ◽  
JingyaWei ◽  
Fengtao Ma ◽  
Qiang Shan ◽  
Duo Gao ◽  
...  
Keyword(s):  
Pineal Gland ◽  
Pituitary Gland ◽  
Antioxidant Capacity ◽  
Dopaminergic Neurons ◽  
Growth And Development ◽  
Endocrine System ◽  
Mammary Glands ◽  
Prolactin Secretion ◽  
The Body ◽  
Stimulation Of

In-depth studies have identified many hormones important for controlling mammary growth and maintaining lactation. One of these is melatonin, which is synthesized and secreted by the pineal gland to regulate circadian rhythms, improve antioxidant capacity, and enhance immunity. Prolactin is secreted by the pituitary gland and is associated with the growth and development of mammary glands as well as initiation and maintenance of lactation. The hypothalamus-pituitary system, the most important endocrine system in the body, regulates prolactin secretion mainly through dopamine released from tuberoinfundibular dopaminergic neurons. This review provides a reference for further study and describes the regulation of lactation and prolactin secretion by melatonin, primarily via the protection and stimulation of tuberoinfundibular dopaminergic neurons.

Hypothalamic Hormones: Clinical Aspects

1988 ◽  
Vol 183 (5) ◽  
pp. 532-534
Author(s):  
K. Kamijo ◽  
A. Yachi
Keyword(s):  
Clinical Aspects ◽  
Hypothalamic Hormones
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