| Endocrine roles of D-aspartic acid in the testis of lizard Podarcis s. sicula. | |
| | |
MedLine Citation:
|
PMID: 16423814 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
In the lizard Podarcis s. sicula, a substantial amount of D-aspartate (D-Asp) is endogenous to the testis and shows cyclic changes of activity connected with sex hormone profiles during the annual reproductive phases. Testicular D-Asp content shows a direct correlation with testosterone titres and a reverse correlation with 17beta-estradiol titres. In vivo experiments, consisting of i.p. injections of 2.0 micromol/g body weight of D-Asp or other amino acids, in lizards collected during the three main phases of the reproductive cycle (pre-reproductive, reproductive and post-reproductive period), revealed that the testis can specifically take up and accumulate D-Asp alone. Moreover, this amino acid influences the synthesis of testosterone and 17beta-estradiol in all phases of the cycle. This phenomenon is particularly evident during the pre- and post-reproductive period, when endogenous testosterone levels observed in both testis and plasma were the lowest and 17beta-estradiol concentrations were the highest. D-Asp rapidly induces a fall in 17beta-estradiol and a rise in testosterone at 3 h post-injection in the testis and at 6 h post-injection in the blood. In vitro experiments show that testicular tissue converted L-Asp into D-Asp through an aspartate racemase. D-Asp synthesis was measured in all phases of the cycle, but was significantly higher during the reproductive period with a peak at pH 6.0. The exogenous D-Asp also induces a significant increase in the mitotic activity of the testis at 3 h (P < 0.05) and at 6 h (P < 0.01). Induction of spermatogenesis by D-Asp is recognized by an intense immunoreactivity of the germinal epithelium (spermatogonia and spermatids) for proliferation cell nuclear antigen (PCNA). The effects of D-Asp on the testis appear to be specific since they were not seen in lizards injected with other D- or L-forms of amino acids with known excitatory effects on neurosecretion. Our results suggest a regulatory role for D-Asp in the steroido-genesis and spermatogenesis of the testis of the lizard Podarcis s. sicula. |
| | |
Authors:
|
F Raucci; S D'Aniello; M M Di Fiore |
Related Documents
:
|
5275384 - Bovine parathyroid hormone: amino acid sequence. 1141204 - Growth hormone stimulation of amino acid transport and utilization by the perfused rat ... 3020584 - Contrasting effects of fatty acids on oocyte maturation in several starfish species. 2865104 - Identification of major urinary metabolites of nafarelin acetate, a potent agonist of l... 1016254 - Microbiological degradation of bile acids. the conjugation of a certain cholic acid met... 6696904 - Sodium-dependent uptake of taurine in encapsulated staphylococcus aureus strain m. |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
|
Title: The Journal of endocrinology Volume: 187 ISSN: 0022-0795 ISO Abbreviation: J. Endocrinol. Publication Date: 2005 Dec |
Date Detail:
|
Created Date: 2006-01-20 Completed Date: 2006-02-09 Revised Date: 2006-11-15 |
Medline Journal Info:
|
Nlm Unique ID: 0375363 Medline TA: J Endocrinol Country: England |
Other Details:
|
Languages: eng Pagination: 347-59 Citation Subset: IM |
Affiliation:
|
Department of Life Sciences, Second University of Naples, Via Vivaldi 43, 81100 Caserta, Italy. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Amino Acid Isomerases
/
metabolism Animals D-Aspartic Acid / biosynthesis, physiology* Estradiol / analysis, blood Immunohistochemistry / methods Lizards / anatomy & histology, immunology, physiology* Male Proliferating Cell Nuclear Antigen / analysis Reproduction Spermatids / immunology Spermatogenesis / physiology Spermatogonia / immunology Testis / anatomy & histology, immunology, physiology* Testosterone / analysis, blood |
| Chemical | |
Reg. No./Substance:
|
0/Proliferating Cell Nuclear Antigen; 1783-96-6/D-Aspartic Acid; 50-28-2/Estradiol; 58-22-0/Testosterone; EC 5.1.1.-/Amino Acid Isomerases; EC 5.1.1.13/aspartate racemase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Change in prostaglandin E synthases (PGESs) in microsomal PGES-1 knockout mice in a preterm delivery...
Next Document: Molecular analysis of KAL-1, GnRH-R, NELF and EBF2 genes in a series of Kallmann syndrome and normos...