Mesotocin and Arginine-Vasopressin in the Corpus Luteum of an Australian Marsupial, the Brushtail Possum (Trichosurus vulpecula)

doi:10.1006/gcen.1994.1023

General and Comparative Endocrinology

Volume 93, Issue 2, February 1994, Pages 197-204

https://doi.org/10.1006/gcen.1994.1023 Get rights and content

Abstract

The neuropeptide hormones arginine-vasopressin (AVP) and oxytocin (OT) have been found in the ovarian follicles and corpora lutea (CL) of many eutherian mammals. In ruminants, there is persuasive evidence that luteal OT is involved in luteolysis via stimulation of uterine prostaglandins. However, based on scant evidence, the marsupial ovary has been viewed as being devoid of OT-like and AVP-like peptides. In this study, corpora lutea from the brushtail possum were examined for OT, AVP, and mesotocin (MT) by a combination of reverse phase HPLC, radioimmunoassay, and immunohistochemistry (IHC). Peptides extracted from each of five CL were separated by HPLC and each fraction was assayed for AVP, MT, and OT. Two immunoreactive peaks were found, corresponding to AVP and MT standards. The amount of each peptide was 8.7 ± 2.22 pmol MT/g (mean ± SEM) and 5.7 ± 1.0 pmol AVP/g, respectively. The mean MT/AVP ratio was 1.55 compared to 0.26 for the pituitary, IHC (streptavidin-peroxidase method) of Bouin's-fixed CL showed staining for MT in the cytoplasm of luteal cells which was absent in stromal tissue and nonluteal ovarian tissue. Not all luteal cells were immunopositive and no topographical distribution of stained cells was observed. IHC localization of AVP was not attempted. It was concluded that the CL of the brushtail possum contains low quantities of MT and AVP, which in the case of MT is probably synthesized by the immunochemically staining cells of the CL.

References (0)

Cited by (12)

Structural and functional diversity of nonapeptide hormones from an evolutionary perspective: A review
2017, General and Comparative Endocrinology
Citation Excerpt :
However, there are also several reports on the presence of the nonapeptides in non-classical, non-neuronal sites (Clements and Funder, 1986; Saito and Grossmann, 1999), especially in reproductive tissues. Nonapeptides have been demonstrated to be present in female reproductive tissues like ovary (Saito et al., 1990; Wathes et al., 1983), corpus luteum (Sernia et al., 1994; Wathes et al., 1983), follicular fluid (Schaeffer et al., 1984) and uterus. It has also been demonstrated in testis (Kasson and Hseuh, 1986; Nicholson et al., 1984).
The article presents an overview of the comparative distribution, structure and functions of the nonapeptide hormones in chordates and non chordates. The review begins with a historical preview of the advent of the concept of neurosecretion and birth of neuroendocrine science, pioneered by the works of E. Scharrer and W. Bargmann. The sections which follow discuss different vertebrate nonapeptides, their distribution, comparison, precursor gene structures and processing, highlighting the major differences in these aspects amidst the conserved features across vertebrates. The vast literature on the anatomical characteristics of the nonapeptide secreting nuclei in the brain and their projections was briefly reviewed in a comparative framework. Recent knowledge on the nonapeptide hormone receptors and their intracellular signaling pathways is discussed and few grey areas which require deeper studies are identified. The sections on the functions and regulation of nonapeptides summarize the huge and ever increasing literature that is available in these areas. The nonapeptides emerge as key homeostatic molecules with complex regulation and several synergistic partners. Lastly, an update of the nonapeptides in non chordates with respect to distribution, site of synthesis, functions and receptors, dealt separately for each phylum, is presented. The non chordate nonapeptides share many similarities with their counterparts in vertebrates, pointing the system to have an ancient origin and to be an important substrate for changes during adaptive evolution. The article concludes projecting the nonapeptides as one of the very first common molecules of the primitive nervous and endocrine systems, which have been retained to maintain homeostatic functions in metazoans; some of which are conserved across the animal kingdom and some are specialized in a group/lineage-specific manner.
Non-Mammalian Oxytocin Family Peptides
2015, Handbook of Hormones: Comparative Endocrinology for Basic and Clinical Research
All non-mammalian tetrapods, lungfishes, and coelacanths have mesotocin (MT), while ray-finned fish have isotocin (IT). Batoids and holocephalans have glumitocin and OT, respectively, but sharks have two distinct peptides. From cartilaginous fishes to birds, OT family peptide genes are located on the same chromosome with the VT gene in tail-to-head orientation. Cyclostomes do not have an OT family peptide. OT family peptides are implicated in salt and water balance, but are less potent when compared with vasotocin. Widespread distribution of MT and IT receptors suggests their diverse functions. Similar to mammalian OT, contributions of MT and IT to social and sexual behaviors are implicated. Knockdown of MT produces female-specific deficits in gregariousness, pair bonding, and nest cup ownership in finches. The knockdown also modulates stress coping, and induces hyperphagia in males.
The corpus luteum and interstitial tissue in a marsupial, the brushtail possum (Trichosurus vulpecula)
2002, Molecular and Cellular Endocrinology
The Australian brushtail possum (Trichosurus vulpecula) is a nocturnal, arboreal marsupial. It has become a pest of significant ecological and economic importance in New Zealand, and thus a renewed interest in understanding the reproductive biology of this species has been generated. The corpus luteum (CL) in possums is a largely autonomous gland in that it does not rely on pituitary hormones to function and is not responsive to luteolytic agents for its demise. Its importance in regulating the oestrous cycle and pregnancy has been established; however, little is known regarding the mechanisms involved in its function. Interstitial tissue (IT) is a prominent feature found throughout the ovarian stroma, yet little is known regarding the origin or function of these cells. Based on histological examinations, our data support the hypothesis that interstitial tissue arises from a unique cell type called medullary cords during early ovarian development. Using possum-specific probes for proteins involved in steroidogenesis, receptors for pituitary hormones and members of the TGF-β superfamily we have initiated studies investigating the expression of genes that may be important in the function and regulation of the CL and interstitial tissue. Results show that both tissues are steroidogenic and that both express receptors for prolactin and luteinising hormone (LH). Collectively these findings suggest that prolactin and LH may be important in the regulation of steroidogenesis in the CL and interstitial tissue in possums.
Mammalian mesotocin: cDNA sequence and expression of an oxytocin-like gene in a macropodid marsupial, the tammar wallaby
2000, General and Comparative Endocrinology
The oxytocin (OT)-like peptide of most Australian marsupials is mesotocin (MT), which differs from OT by substitution of isoleucine for leucine at position 8. To date, the only information on the evolution of the OT peptide in marsupials is based on the sequence of the 9-amino acid peptide itself. The main objective of this study was to obtain the nucleotide and derived amino acid sequences of a marsupial MT precursor for comparison with known OT and MT precursors of eutherians and nonmammalian vertebrates. The structural organization and sequence of the MT gene and its specific transcript were established in a macropodid marsupial, the tammar wallaby, using PCR strategies with a combination of genomic DNA and reverse-transcribed hypothalamic RNA. A consensus genomic sequence of 1221 bp was produced which, by comparison with the expressed cDNA sequence, included two intron sequences of 480 and 188 bp. The tammar MT precursor molecule consists of a 32-amino acid signal peptide, followed by the MT-encoding region and the Gly-Lys-Arg carboxy-terminal cleavage and amidation signal which separates the nonapeptide from the 92-amino acid neurophysin. At the amino acid level, the MT precursor is more similar to eutherian OT precursors than to nonmammalian MT, isotocin, or vasotocin precursors. Northern analysis demonstrated a single transcript of approximately 0.6 kB in the hypothalamus. Mesotocin mRNA is also present in several tissues of the reproductive tract, including the corpus luteum, follicle, uterus, and placenta. Within the ovary, MT transcripts are localized predominantly in the granulosa cells of antral follicles with some positive hybridization signals in cells of the theca interna. This pattern of MT gene expression in marsupials is very similar to that of OT in eutherians and suggests a conserved physiology in the mammalian ovary.
Neurohypophysial and paracrine vasopressinergic signaling regulates aquaporin trafficking to hydrate marine teleost oocytes
2023, Frontiers in Endocrinology
Molecular cloning, sequencing and tissue expression of vasotocin and isotocin precursor genes from Ostariophysian catfishes: Phylogeny and evolutionary considerations in teleosts
2015, Frontiers in Neuroscience

View all citing articles on Scopus

View full text

Regular ArticleMesotocin and Arginine-Vasopressin in the Corpus Luteum of an Australian Marsupial, the Brushtail Possum (Trichosurus vulpecula)

Abstract

Regular Article
Mesotocin and Arginine-Vasopressin in the Corpus Luteum of an Australian Marsupial, the Brushtail Possum (Trichosurus vulpecula)