Hypothalamic Control of MSH Secretion in Lower Vertebrates

2015 ◽  
pp. 51-62 ◽  
Author(s):  
H. J. Th. Goos ◽  
M. Terlou
Keyword(s):  
Lower Vertebrates ◽  
Hypothalamic Control

Role of LPXRFamide peptide in the neuroendocrine regulation of reproduction in fish

2011 ◽  
Vol 6 (5) ◽  
pp. 853-860 ◽  
Author(s):  
Md. Shahjahan ◽  
Hironori Ando
Keyword(s):  
Gonadal Development ◽  
Gonadotropin Releasing Hormone ◽  
Fish Reproduction ◽  
Lower Vertebrates ◽  
Hypothalamic Control ◽  
G Protein Coupled ◽  
Made In

AbstractThe decapeptide gonadotropin-releasing hormone (GnRH) is the primary factor responsible for the hypothalamic control of gonadotropin (GTH) secretion. This review focuses on a family of neuropeptides, LPXRFamide (LPXRFa) peptides, which have been implicated in the regulation of GTH secretion. LPXRFa acts on the pituitary via a G protein-coupled receptor, LPXRFa-R, to enhance gonadal development and maintenance by increasing gonadotropin release and synthesis. Because LPXRFa exists and functions in several fish species, LPXRFa is considered to be a key neurohormone in fish reproduction control. The precursors to LPXRFamide peptides encoded plural LPXRFamide peptides and were highly divergent in vertebrates, particularly in lower vertebrates. Tissue distribution analyses indicated that LPXRFamide peptides were highly concentrated in the hypothalamus and other brainstem regions. In view of the localization and expression of LPXRFamide peptides in the hypothalamo-hypophysial system, LPXRFamide peptide in fish increase GTH release in vitro and in vivo. This review summarizes the advances made in our understanding of the biosynthesis, mode of action and functional significance of LPXRFa, a newly discovered key neurohormone.

ACTION OF ENZYME DIGESTED PITUITARY GLANDS OF THE SKIPPER-FROG ON THE OVULATION OF THE SAME

1960 ◽  
Vol XXXIII (II) ◽  
pp. 255-260 ◽  
Author(s):  
L. S. Ramaswami ◽  
A. B. Lakshman
Keyword(s):  
Pituitary Gland ◽  
Constant Temperature ◽  
Constant Temperature Bath ◽  
Predominant Role ◽  
Lower Vertebrates ◽  
Pituitary Glands ◽  
Stimulating Factor

ABSTRACT By using enzymes, the gonadotrophic factors in the skipper-frog pituitary glands have been selectively inactivated or destroyed. By incubating a known number of pituitary gland homogenate with ptyalin in a constant temperature bath for 5–6 h the follicle-stimulating factor is inactivated; with trypsin or pepsin, the luteinizing factor is inactivated. Bioassay on gravid skipper-frogs indicate that the ptyalin digested homogenate brings about profuse spawning while the trypsin or pepsin digested homogenates do not. When a combination of ptyalin digested and trypsin digested homogenates is injected into fresh gravid skipper-frogs, poor spawning is brought about. These experiments show that the luteinizing factor alone brings about more profuse spawning than when it is combined with the follicle-stimulating factor. It is likely, therefore, that in the lower vertebrates the luteinizing factor of the pituitary gland plays a more predominant role. The exact proportions in which the different dosages for the control and test animals are administered are also tabulated.

scholarly journals Cardiac regeneration: epicardial mediated repair

2015 ◽  
Vol 282 (1821) ◽  
pp. 20152147 ◽  
Author(s):  
Teresa Kennedy-Lydon ◽  
Nadia Rosenthal
Keyword(s):  
Stem Cells ◽  
Endothelial Cells ◽  
Cardiac Fibroblasts ◽  
Cardiac Regeneration ◽  
Repair Process ◽  
Regenerative Process ◽  
Cardiac Stem Cell ◽  
Cardiomyocyte Proliferation ◽  
Lower Vertebrates

The hearts of lower vertebrates such as fish and salamanders display scarless regeneration following injury, although this feature is lost in adult mammals. The remarkable capacity of the neonatal mammalian heart to regenerate suggests that the underlying machinery required for the regenerative process is evolutionarily retained. Recent studies highlight the epicardial covering of the heart as an important source of the signalling factors required for the repair process. The developing epicardium is also a major source of cardiac fibroblasts, smooth muscle, endothelial cells and stem cells. Here, we examine animal models that are capable of scarless regeneration, the role of the epicardium as a source of cells, signalling mechanisms implicated in the regenerative process and how these mechanisms influence cardiomyocyte proliferation. We also discuss recent advances in cardiac stem cell research and potential therapeutic targets arising from these studies.

Biological Sciences: N-Terminal Sequences of Immunoglobulin Heavy and Light Chains from Three Species of Lower Vertebrates

Nature ◽  
1970 ◽  
Vol 228 (5275) ◽  
pp. 991-992 ◽  
Author(s):  
RONALD T. ACTON ◽  
PETER F. WEINHEIMER ◽  
MICHAEL WOLCOTT ◽  
E. EDWARD EVANS ◽  
J. C. BENNETT
Keyword(s):  
Biological Sciences ◽  
Light Chains ◽  
Lower Vertebrates

EFFECTS OF SEROTONIN ON SPONTANEOUS OVULATION: A THEORY FOR THE DUAL HYPOTHALAMIC CONTROL OF OVULATION

1971 ◽  
Vol 68 (2) ◽  
pp. 334-344 ◽  
Author(s):  
Anant P. Labhsetwar
Keyword(s):  
Serotoninergic System ◽  
Dual Control ◽  
Inhibitory Effects ◽  
Catecholaminergic System ◽  
Peripheral Mechanism ◽  
Ovulation Inhibition ◽  
Oestradiol Benzoate ◽  
Hypothalamic Control ◽  
Specific Antagonist

ABSTRACT In an attempt to study the inhibitory effects of serotonin on spontaneous ovulation, the monoamine was administered subcutaneously to rats with 4-day oestrous cycles. Administration (50 mg/kg) at 5.00 p. m. on the day before pro-oestrus interfered with ovulation without affecting vaginal cornification, uterine ballooning or mating. This effect on ovulation could be overcome with methysergide, a specific antagonist of serotonin. Administration, at appropriate times, of LH or oestradiol benzoate or the stimulus provided by mating prevented the inhibitory effects of serotonin. implicating a central rather than a peripheral mechanism in interference with ovulation. This was further confirmed by the persistence in the serotonin-treated animals of high levels of pituitary LH, comparable to pro-oestrous levels. It is probable that serotonin blocked ovulation by augmenting the inhibitory effects of serotoninergic fibres in the hypothalamus. It is postulated on the basis of the present results and those reported in the literature that the hypothalamus exercises a dual control over ovulation, inhibitory influences being transmitted through serotonin-linked neurones while stimulatory effects are delivered via catecholaminergic fibres to neurones which synthesize releasing factor(s) for the ovulating hormone. It is postulated that a certain degree of balance in favour of the catecholaminergic system is necessary for the occurrence of ovulation. Inhibition of ovulation occurs whenever the serotoninergic system gains dominance over catecholaminergic system. The theory can account for the effects on ovulation of a multitude of chemically diverse agents reported in the literature.

IODINE METABOLISM IN LOWER VERTEBRATES

2006 ◽  
Vol 86 (2) ◽  
pp. 316-353 ◽  
Author(s):  
J. Leloup ◽  
M. Fontaine
Keyword(s):  
Lower Vertebrates ◽  
Iodine Metabolism

scholarly journals Low‐molecular‐weight phosphotyrosyl protein phosphatase expression in brain of chicken and some lower vertebrates

2002 ◽  
Vol 69 (2) ◽  
pp. 97-102
Author(s):  
Livia Lucentini ◽  
Antonella Angiolillo ◽  
Emanuela Varasano ◽  
Fausto Panara
Keyword(s):  
Molecular Weight ◽  
Protein Phosphatase ◽  
Low Molecular Weight ◽  
Lower Vertebrates
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