Reproductive

Agnew, D.W., L. Munson, and E.C. Ramsay (2004). Cystic endometrial hyperplasia in elephants. Veterinary Pathology 41(2): 179-83.
NAL Call Number: 41.8 P27
Abstract: Most captive female elephants are nulliparous and aged and many have endometrial disease, factors that may hinder fertility. This study characterized the pathologic features and demographic distribution of endometrial lesions from 27 captive Asian (Elephas maximus) and 13 African elephants (Loxodonta africanus), 12- to 57-years of age. The principal lesion was marked cystic and polypoid endometrial hyperplasia (CEH), present in 67% of Asian and 15% of African elephants ranging from 26 to 57 years. The lower prevalence in African elephants likely reflects their younger age range in this study. Fourteen of 15 affected elephants with breeding information were nulliparous. These results suggest that CEH and polyps are common in aged nulliparous elephants, and the severity of these lesions may impair fertility. These findings will be useful in the interpretation of ultrasonographic findings during reproductive examinations of potential breeding cows. Also, breeding programs should focus on younger animals.
Descriptors: zoo animals, endometrial hyperplasia, endometrium pathology, fertility physiology, polyps, endometrial hyperplasia pathology, histological techniques, polyps pathology, species specificity.

Allen, W. R (2006). Review. Ovulation, pregnancy, placentation and husbandry in the African elephant (Loxodonta africana). Philosophical Transactions of the Royal Society of London. Series B Biological Sciences 361(1469): 821-34.
NAL Call Number: 501 L84Pb
Abstract: 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 5alpha-dihydryoprogesterone and other 5alpha 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.
Descriptors: African elephant, ovulation, placentation, husbandry, puberty, estrus cycles, pregnancy, endometrium, gestation, corpora lutea.

Allen, W.R., S. Mathias, and M. Ford (2005). Placentation in the African elephant, Loxodonta africana. IV. Growth and function of the fetal gonads. Reproduction 130(5): 713-720. ISSN: 1470-1626.
NAL Call Number: QP251.J75
Abstract: 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 5[alpha]-dihydroprogesterone and other 5[alpha]-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.
Descriptors: African elephant, placentation, fetal gonads, ovaries, testes, gestation, growth, function, corpora lutea, follicles, seminiferous tubules.

Allen, W.R., S. Mathias, F.B. Wooding, and R.J. van Aarde (2003). Placentation in the African elephant (Loxodonta africana). II. Morphological changes in the uterus and placenta throughout gestation. Placenta 24(6): 598-617.
NAL Call Number: QP281.P53
Abstract: The gross and microscopic development of the zonary endotheliochorial placenta in the African elephant was studied in 22 gravid uteri that ranged in gestational stage from 0.5 to 20.6 months. The conceptus only ever occupies one horn of the uterus and is associated with 2-5 large corpora lutea that persist in the ipsilateral ovary throughout gestation. Initially, the trophoblast in the equatorial region of the conceptus completely replaces the lumenal epithelium of the endometrium to which it is apposed. Blunt upgrowths of endometrial stroma then develop, each closely invested by trophoblast, and containing the capillaries that will vascularize this maternal component of the resulting placental band. With advancing gestation the lamellate stromal upgrowths increase markedly in length and become much thinner, thereby bringing the trophoblast into intimate contact with the endothelium of the maternal capillaries. They also become folded or pleated to increase the total area of intimate feto-maternal contact. At the lateral edges of the placental band the lamellae bend over towards the endometrium to form a blind cleft. Leakage of blood into this area creates haemophagous zones in which phenotypically specialized trophoblast cells phagocytose the blood components. The presence of large resorbing blood clots and circumferential scars in the uteri of three post parturient animals initiated the hypothesis that, when the standing elephant gives birth at term, the passage of the 120 kg fetus through the vagina may wrench the placenta off the endometrium by severing its very narrow maternal placental hilus. The resulting intrauterine haemorrhage may then play a role in preventing further conception for around 2 years.
Descriptors: physiology, placenta embryology, placentation physiology, uterus anatomy and histology, gestational age, placenta physiology, trophoblasts physiology, trophoblasts ultrastructure, uterus physiology.

Brown, J.L., D. Olson, M. Keele, and E.W. Freeman (2004). Survey of the reproductive cyclicity status of Asian and African elephants in North America. Zoo Biology 23(4): 309-321. ISSN: 0733-3188.
NAL Call Number: QL77.5.Z6
Descriptors: reproductive cyclicity, status, survey, African elephant, Asian elephant, North America.

Brown, J.L., S.L. Walker, and T. Moeller (2004). Comparative endocrinology of cycling and non-cycling Asian (Elephas maximus) and African (Loxodonta africana) elephants. General and Comparative Endocrinology 136(3): 360-70.
NAL Call Number: 444.8 G28
Abstract: Up to 14% of Asian and 29% of African elephants in captivity are not cycling normally or exhibit irregular cycles based on progestin profiles. To determine if ovarian acyclicity is related to other disruptions in endocrine activity, serum pituitary, thyroid, adrenal, and ovarian hormones in weekly samples collected for 6-25 months were compared between normal cycling (n=22 each species) and non-cycling (n=6 Asian; n=30 African) elephants. A subset of cycling females (n=4 Asian, 7 African) also were blood sampled daily during the follicular phase to characterize the peri-ovulatory period. In normal cycling females, two leutinizing hormone (LH) surges were observed 3 weeks apart during a normal follicular phase, with the second inducing ovulation (ovLH). Serum FSH concentrations were highest at the beginning of the non-luteal phase, declining to nadir concentrations within 4 days of the ovLH surge. FSH remained low until after the ovLH surge and then increased during the luteal phase. A species difference was noted in prolactin secretion. In the African elephant, prolactin was increased during the follicular phase, but in Asian elephants concentrations remained stable throughout the cycle. Patterns of thyroid hormones (thyroid-stimulating hormone, TSH; free and total thyroxine, T4; free and total triiodothyronine, T3) and cortisol secretion were not affected by estrous cycle stage or season in cycling elephants. In non-cycling elephants, there were no fluctuating patterns of LH, FSH, or prolactin secretion. Overall mean concentrations of all hormones were similar to those in cycling animals, with the exception of FSH, prolactin, and estradiol. Mean serum FSH concentrations were lower due to females not exhibiting normal cyclic increases, whereas serum estradiol was higher overall in most acyclic females. Prolactin concentrations were significantly increased in 11 of 30 non-cycling females, all of which were African elephants. In sum, while there were no consistent endocrine anomalies associated with ovarian acyclicity, hyperprolactinemia may be one cause of ovarian dysfunction. The finding of elevated estrogens in some acyclic females also deserves further investigation, especially determining how it relates to reproductive tract pathologies.
Descriptors: physiology, estrous cycle physiology, ovary physiology, blood, estradiol blood, estrous cycle blood, follicle stimulating hormone blood, hydrocortisone blood, luteinizing hormone blood, prolactin blood, seasons, species specificity, thyrotropin blood, thyroxine blood, triiodothyronine blood.

Dahl, N.J., D. Olson, D.L. Schmitt, D.R. Blasko, R.S. Kristipati, and J.F. Roser (2004). Development of an enzyme-linked immunosorbent assay (ELISA) for luteinizing hormone (LH) in the elephant (Loxodonta africana and Elephas maximus). Zoo Biology 23(1): 65-78. ISSN: 0733-3188.
NAL Call Number: QL77.5.Z6
Descriptors: African elephant, Asian elephant, ELISA, luteinizing hormone, enzyme-linked immunosorobent assay, LH, development.

Dill, W.M., B.L. Davis, A.R. Hicks, T.E. Goodwin, L.E.L. Rasmussen, H. Loizi, and B. Schulte (2003). Chemical analysis of preovulatory female African elephant urine: a search for putative pheromones. Abstracts of Papers American Chemical Society 225(1-2): CHED 409. ISSN: 0065-7727.
NAL Call Number: 381 Am33PA
Descriptors: African elephant, urinary system, chemical analysis, urine, putative pheromones, preovulatory, female.

Freeman, E.W., E. Weiss, and J.L. Brown (2004). Examination of the interrelationships of behavior, dominance status, and ovarian activity in captive Asian and African elephants. Zoo Biology 23(5): 431-448. ISSN: 0733-3188.
NAL Call Number: QL77.5.Z6
Descriptors: ovarian activity, Asian elephants, African elephants, dominance status, behavior, interrelationships.

Ganswindt, A., H.B. Rasmussen, M. Heistermann, and J.K. Hodges (2005). The sexually active states of free-ranging male African elephants (Loxodonta africana): defining musth and non-musth endocrinology, physical signals, and behavior. Hormones and Behavior 47(1): 83-91. ISSN: 0018-506X.
NAL Call Number: QP801.H7H64
Descriptors: African elephant, Loxodonta africana, reproductive behavior, musth, characteristics, free ranging males, Kenya, temporal glands, secretions, glucocorticoid, urine dribbling, androgen levels, aggressive behavior.

Goodwin, T.E. and L.E.L. Rasmussen (2004). Collaborative research at the interface of chemistry and biology: development and identity of sexually dimorphic reproductive signals and responses by African elephants. Abstracts of Papers American Chemical Society 227(Part 1): U658. ISSN: 0065-7727.
NAL Call Number: 381 Am33PA
Descriptors: reproductive system, chemistry, biology, African elephants, research, reproductive signals.

Jones, C.J., F.B. Wooding, S.S. Mathias, and W.R. Allen (2004). Fetomaternal glycosylation of early placentation events in the African elephant Loxodonta africana. Placenta 25(4): 308-20.
NAL Call Number: QP281.P53
Abstract: During implantation in the African elephant (Loxodonta africana), fetal trophoblast displaces the surface uterine epithelium and superficially penetrates the uterine glands. This limited invasion is followed by the upgrowth of blunt fingers of endometrial stroma, covered with trophoblast and containing capillaries that subsequently vascularize the growing placenta. We have used lectin histochemistry to compare the glycosylation of maternal endothelial cells in the endometrium with those growing within the trophoblastic processes of a 2 g embryo (approximately 125 days' gestation), and also examine changes in the endometrial glands associated with trophoblastic invasion. Maternal vessels at the apices of the trophoblast-covered stromal upgrowths showed increased expression of terminal N-acetyl galactosamine, N-acetyl glucosamine oligomers, some sialic acids, and tri/tetra-antennate non-bisected complex N-linked glycan, as indicated by increased lectin staining. The areas of increased staining were also more resistant to neuraminidase digestion. Invaded glands had distended walls composed of flattened epithelial cells, some of which showed heavy lectin staining suggestive of intracellular glycan accumulation. The vascular changes suggest that new maternal capillary growth is accompanied by alterations in surface glycosylation. This may be the result of increased glycosyl transferase activity associated with cell proliferation and may also indicate the expression of significantly increased anti-adhesive molecules preventing blood stasis and egress of maternal immunocompetent cells into the fetal compartment.
Descriptors: physiology, embryo implantation physiology, maternal fetal exchange physiology, trophoblasts metabolism, biological markers analysis, endometrium metabolism, gestational age, glycosylation, immunoenzyme techniques, lectins metabolism.

Leong, K., K. Burks, C. Rizkalla, and A. Savage (2005). Effects of reproductive and social context on vocal communication in captive female African elephants (Loxodonta africana). Zoo Biology 24(4): 331-347. ISSN: 0733-3188.
NAL Call Number: QL77.5.Z6
Descriptors: African elephant, Loxodonta africana, reproduction, acoustic signals, female vocalizations, communication, social context effects, LWP frequency vocalizations, long distances, social behavior.

Ortolani, A., K. Leong, L. Graham, and A. Savage (2005). Behavioral indices of estrus in a group of captive African elephants (Loxodonta africana). Zoo Biology 24(4): 311-329. ISSN: 0733-3188.
NAL Call Number: QL77.5.Z6
Descriptors: estrous cycle, sexual behavior, flehmen, estrus detection, males, females.

Stumpf, P. and U. Welsch (2004). Secretory and defensive functions of the duct system of the lactating mammary gland of the African elephant (Loxodonta africana, Proboscidea). Zoomorphology (Berlin) 123(3): 155-167. ISSN: 0720-213X.
NAL Call Number: 442.8 Z33
Descriptors: African elephant, mammary gland, lactating, duct system, secretory, defensive functions, microorganisms, invading, IgA, lactation period.

Wooding, F.B., F. Stewart, S. Mathias, and W.R. Allen (2005). Placentation in the African elephant, Loxodonta africanus. III. Ultrastructural and functional features of the placenta. Placenta 26(6): 449-70.
NAL Call Number: QP281.P53
Abstract: Successful transfer of nutrients to the elephant fetus during pregnancy relies on a variety of placental modifications. Our light and electron microscopical investigations show that the structure is endotheliochorial from implantation to term, with unicellular, never syncytial trophoblast. Light and electron microscope immunocytochemistry shows the restriction of the glucose transporter 1 isoform to the basolateral surfaces of the trophoblast, with the glucose transporter 3 restricted to the apical plasmalemma of the trophoblast. Glucose transport to the fetus therefore requires a sequential use of both isoforms. Light and electron microscope cytochemistry indicate the presence of iron deposits only in the haemophagous zones confirming their iron transport function. No trophoblast areas with high concentrations of Calcium binding protein, specialised for Calcium transport were found. In situ hybridisation demonstrated the presence of IGF-II mRNA in the trophoblast from the earliest stage, with TGFbeta1 and HGF-SF mRNA expressed subsequently but only IGF-II and HGF mRNA present in the second half of pregnancy. The results are briefly discussed in terms of placental growth and function and indicate that the elephant placenta is another example of a unique solution to the variety of problems posed by a resident fetus.
Descriptors: physiology, placenta cytology, placenta physiology, pregnancy, calcium binding proteins metabolism, embryo implantation physiology, epidermal growth factor genetics, glucose transporter type 1, glucose transporter type 3, hepatocyte growth factor genetics, immunohistochemistry, in situ hybridization, insulin like growth factor II genetics, iron metabolism, keratin metabolism, microscopy, electron, monosaccharide transport proteins metabolism, nerve tissue proteins metabolism, proto oncogene proteins C met metabolism, transforming growth factor beta genetics, trophoblasts metabolism, trophoblasts ultrastructure.