scholarly journals Placentation in the African elephant, Loxodonta africana. IV. Growth and function of the fetal gonads

Reproduction ◽  
2005 ◽  
Vol 130 (5) ◽  
pp. 713-720 ◽  
Author(s):  
W R Allen ◽  
S Mathias ◽  
M Ford
Keyword(s):  
Stromal Cells ◽  
Loxodonta Africana ◽  
Interstitial Cells ◽  
African Elephant ◽  
Seminiferous Tubules ◽  
Corpora Lutea ◽  
And Function

The gonads, both ovaries and testes, of 44 elephant fetuses weighing 0.09–112 kg (6.1–21.3 months gestation) were examined grossly and histologically. As in equids, elephant fetal gonads undergo a phase of marked growth and enlargement during the second half of gestation, which is more pronounced in ovaries than testes due to growth and antrum formation of numerous follicles in the former. Stromal cells undergo hypertrophy and transformation to form zones of interstitial cells that are associated with the enlarged follicles in the ovaries and in which the primitive seminiferous tubules are embedded in the testes. The interstitial cells have the capacity to synthesize 5α-dihydroprogesterone and other 5α-reduced progestagens from cholesterol and pregnenelone and the hypothesis is raised that these fetal gonadal progestagens may supplement significantly the progestagens secreted by the multiple large corpora lutea of pregnancy in the elephant.

scholarly journals Luteal maintenance of pregnancy in the African elephant (Loxodonta africana)

Reproduction ◽  
2012 ◽  
Vol 143 (6) ◽  
pp. 845-854 ◽  
Author(s):  
F J Stansfield ◽  
W R Allen
Keyword(s):  
Loxodonta Africana ◽  
Hydroxysteroid Dehydrogenase ◽  
Interstitial Cells ◽  
African Elephant ◽  
Oestrous Cycle ◽  
Degenerative Changes ◽  
Gestation Period ◽  
Placental Lactogen ◽  
Corpora Lutea ◽  
Luteal Cells

The ovaries of eight African elephant foetuses and their mothers between 2 and 22 months of gestation, and those of two cycling and two lactating elephants, were examined grossly, histologically and immunocytochemically, with emphasis on the development and regression of accessory corpora lutea (CL) of pregnancy and the steroidogenic capacities of the accessory CL and the foetal ovaries. The results supported recent findings that the accessory CL form as a result of luteinisation, with and without ovulation, of medium-sized follicles during the 3-week inter-luteal period of the oestrous cycle. They enlarge significantly and become steroidogenically active around 5 weeks of gestation, probably in response to the placental lactogen which is secreted by the implanting trophoblast of the conceptus. The large luteal cells stained strongly for 3β hydroxysteroid dehydrogenase (3βHSD) activity throughout the 22-month gestation period although they showed vacuolation and other degenerative changes in the final months of gestation coincident with hypertrophy and hyperplasia of 3βHSD-positive interstitial cells in the foetal gonads. It is proposed that the progestagens secreted by the enlarged gonads of the elephant foetus may function both to assist the maternal ovaries in supporting the pregnancy state and to induce torpor and intrauterine immobility of the rapidly growing foetus.

scholarly journals Ovulation, pregnancy, placentation and husbandry in the African elephant ( Loxodonta africana )

2006 ◽  
Vol 361 (1469) ◽  
pp. 821-834 ◽  
Author(s):  
W.R Allen
Keyword(s):  
South Africa ◽  
Population Density ◽  
Blood Vessel ◽  
Ferric Iron ◽  
Loxodonta Africana ◽  
African Elephant ◽  
Corpora Lutea ◽  
Gestation Length ◽  
In Captivity ◽  
In The Wild

The African elephant reproduces so efficiently in the wild that overpopulation is now a serious problem in some game parks in Zimbabwe, Botswana and South Africa. The female reaches puberty between 10 and 12 years of age in the wild and, when in captivity, shows oestrous cycles of 14–15 weeks duration. She readily conceives a singleton in the wild yet her uterus has the capacity for twins. She shows a gestation length of 22 months and, in the wild, shows a population density and feed dependent intercalving interval of 4–8 years. The trophoblast erodes the lumenal epithelium of the endometrium and stimulates upgrowths of blood vessel-containing stromal villi, which develop eventually into the broad, tightly folded lamellae of the zonary, endotheliochorial placenta. Significant quantities of leaked maternal erythrocytes and ferric iron are phagocytosed by specialized trophoblast cells in the haemophagous zones at the lateral edges of the placental band. Although the placenta itself is endocrinologically inert, the foetal gonads, which enlarge greatly during the second half of pregnancy can synthesize 5α-dihydryoprogesterone and other 5α pregnane derivatives from cholesterol and pregnenolone. These products may synergize with progestagens secreted by the 2–8 large corpora lutea which are always present in the maternal ovaries throughout gestation to maintain the pregnancy state.

46 Morphologic and functional characterization of the early fetal equine gonads

2019 ◽  
Vol 31 (1) ◽  
pp. 149
Author(s):  
D. Scarlet ◽  
I. Walter ◽  
S. Handschuh ◽  
R. Ellerbrock ◽  
I. Canisso ◽  
...  
Keyword(s):  
Germ Cells ◽  
Primordial Germ Cells ◽  
Functional Characterization ◽  
Basal Membrane ◽  
Interstitial Cells ◽  
Germinal Epithelium ◽  
Surface Epithelium ◽  
Seminiferous Tubules ◽  
Stem Cell Markers ◽  
And Function

In the equine embryo, putative primordial germ cells appear between 20 and 30 days and the gonadal primordium can first be identified at Day 30 after ovulation, respectively. Subsequently, sexual differentiation of the gonad occurs and completes by Day 45 of pregnancy. The objectives of this work were to describe the morphology and function of the fetal equine ovary and testis at the beginning of the fetal stage of pregnancy. For this purpose, 12 equine fetuses (6 males and 6 females) were collected at 45 days (n=1, female), 50 days (n=1, male), and 60 days (n=10, 5 males and 5 females) after ovulation, respectively. A high attention was given to Day 60 because it is the representative time for fetal sex determination in horses by transrectal ultrasonography. Conceptuses were collected transcervically by uterine lavage and fixed in 4% formaldehyde before being prepared for morphology analysis and immunohistochemistry assay. Gonads were identified and immunostained for anti-Müllerian hormone (AMH), Ki67, CD117, LIN28, vimentin, cytokeratin, and laminin. In all fetuses, gonads were situated in a sublumbar localisation and connected with the mesonephros. In females, primordial germ cells were localised close to the surface germinal epithelium, whereas in males the primordial germ cells were organised in cord-like clusters-the future seminiferous tubules. At this stage, interstitial cells predominate in the testes. The AMH staining was strongly expressed in the fetal testis, but was completely absent from the fetal ovary. Protein expression of mitosis marker Ki67 was localised in primordial germ cells of both sexes. Moreover, stem cell markers LIN28 and CD117 were also present in the gonads. In females, these proteins were not only localised in some of the primordial germ cells, but also in the surface germinal epithelium, whereas in males LIN28 and CD117 were immunolocalized in the seminiferous tubules, distant from the surface epithelium. Vimentin was strongly expressed in the interstitial cells of the gonads of both sexes. Using laminin staining, basal membrane of the seminiferous tubules in males and of primordial germ cells in females could be visualised. In females, the basal membrane of primordial germ cells also stained positive for cytokeratin, whereas in males no cytokeratin staining was seen around seminiferous tubules. Moreover, the surface germinal epithelium of both sexes stained positive for cytokeratin. This study widely extends existing knowledge about morphology, development, and function of the early fetal equine gonad. Presence of stem cells could be clearly demonstrated in the gonads of both sexes, whereas AMH staining clearly distinguished between males and females, confirming the important role of this hormone for gonadal and reproductive tract differentiation.

Different origins of two corpora lutea recovered from a pregnant African elephant (Loxodonta africana )

2017 ◽  
Vol 52 (6) ◽  
pp. 1138-1141 ◽  
Author(s):  
Y Yamamoto ◽  
K Nagaoka ◽  
Y Kamite ◽  
G Watanabe ◽  
T Allen ◽  
...  
Keyword(s):  
Loxodonta Africana ◽  
African Elephant ◽  
Corpora Lutea ◽  
Different Origins

scholarly journals BIOCHEMICAL OBSERVATIONS ON THE CORPORA LUTEA OF THE AFRICAN ELEPHANT, LOXODONTA AFRICANA

Reproduction ◽  
1969 ◽  
Vol 20 (1) ◽  
pp. 111-117 ◽  
Author(s):  
J. G. SMITH ◽  
J. HANKS ◽  
R. V. SHORT
Keyword(s):  
Loxodonta Africana ◽  
African Elephant ◽  
Corpora Lutea

THE EFFECT OF UNDERNUTRITION AND REHABILITATION ON THE DEVELOPMENT OF THE REPRODUCTIVE ORGANS: RATS

1964 ◽  
Vol 29 (2) ◽  
pp. 119-NP ◽  
Author(s):  
ELSIE M. WIDDOWSON ◽  
W. O. MAVOR ◽  
R. A. McCANCE
Keyword(s):  
Body Weight ◽  
Small Body ◽  
Reproductive Organs ◽  
Ovarian Follicles ◽  
Interstitial Cells ◽  
The Body ◽  
Seminiferous Tubules ◽  
Corpora Lutea ◽  
Food Body

SUMMARY When rats were undernourished so that they gained only 20 g. body weight between the 3rd and the 11th week of life: (1) The testes continued to enlarge; the seminiferous tubules developed, but the interstitial cells regressed. (2) The penis of some of the animals protruded; in others protrusion was first observed on the day after rehabilitation began. (3) The vaginae of more than half the females opened while the animals were still undernourished and had an abnormally small body weight. (4) The ovarian follicles appeared active, but no corpora lutea were found. When the rats were returned to unlimited food, body weight increased, corpora lutea were formed, but the testes remained large as a percentage of the weight of the body.

Inhibition of TMEM16A impedes embryo implantation and decidualization in mice

Reproduction ◽  
2018 ◽  
Author(s):  
Qianrong Qi ◽  
Yifan Yang ◽  
Kailin Wu ◽  
Qingzhen Xie
Keyword(s):  
Progesterone Receptor ◽  
Stromal Cells ◽  
Embryo Implantation ◽  
Mouse Uterus ◽  
Endometrial Stromal Cells ◽  
Uterine Endometrium ◽  
Molecule Inhibitor ◽  
Pathway Inhibition ◽  
And Function ◽  
Reproductive Processes

Recent studies revealed that TMEM16A is involved in several reproductive processes, including ovarian estrogen secretion and ovulation, sperm motility and acrosome reaction, fertilization, and myometrium contraction. However, little is known about the expression and function of TMEM16A in embryo implantation and decidualization. In this study, we focused on the expression and regulation of TMEM16A in mouse uterus during early pregnancy. We found that TMEM16A is up-regulated in uterine endometrium in response to embryo implantation and decidualization. Progesterone treatment could induce TMEM16A expression in endometrial stromal cells through progesterone receptor/c-Myc pathway, which is blocked by progesterone receptor antagonist or the inhibitor of c-Myc signaling pathway. Inhibition of TMEM16A by small molecule inhibitor (T16Ainh-A01) resulted in impaired embryo implantation and decidualization in mice. Treatment with either specific siRNA of Tmem16a or T16Ainh-A01 inhibited the decidualization and proliferation of mouse endometrial stromal cells. In conclusion, our results revealed that TMEM16A is involved in embryo implantation and decidualization in mice, compromised function of TMEM16A may lead to impaired embryo implantation and decidualization.

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