The Physiology and Evolution of Delayed Implantation in Carnivores

Mead, Rodney A.

doi:10.1007/978-1-4613-0855-3_17

Cited by 46 publications

(57 citation statements)

References 111 publications

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“…In these cases, a secondary urinary progestagen rise has occurred 74-122 days after the end of oestrus (Steinman et al 2006) that has suggested a shift in hormonal source, perhaps related to nidation. The giant panda has long been considered to experience delayed implantation (Hodges et al 1984, Monfort et al 1989, Zhang et al 2009), a strictly mammalian strategy prominent in carnivores, especially ursids (Hamlett 1935, Conaway 1971, Weir & Rowlands 1973, Renfree & Calaby 1981, Mead 1989, Sandell 1990, Lindenfors et al 2003, Spady et al 2007. After fertilization, the embryo is sustained as a blastocyst until an unidentified trigger stimulates implantation and resumption of development (Renfree & Calaby 1981, Mead 1989, Sandell 1990).…”

Section: Introductionmentioning

confidence: 99%

“…The giant panda has long been considered to experience delayed implantation (Hodges et al 1984, Monfort et al 1989, Zhang et al 2009), a strictly mammalian strategy prominent in carnivores, especially ursids (Hamlett 1935, Conaway 1971, Weir & Rowlands 1973, Renfree & Calaby 1981, Mead 1989, Sandell 1990, Lindenfors et al 2003, Spady et al 2007. After fertilization, the embryo is sustained as a blastocyst until an unidentified trigger stimulates implantation and resumption of development (Renfree & Calaby 1981, Mead 1989, Sandell 1990). Although peak in urinary progestagens coincides with ultrasonographic foetus detection in giant pandas (Zhang et al 2009), it is unknown whether nidation occurs with the onset of a secondary progesterone (P 4 ) rise, as has been demonstrated in the mink (Mustela vison; Allais & Martinet 1978) Schwarzenberger et al 2004).…”

Section: Introductionmentioning

confidence: 99%

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Unique biphasic progestagen profile in parturient and non-parturient giant pandas (Ailuropoda melanoleuca) as determined by faecal hormone monitoring

Kersey¹,

Wildt²,

Brown³

et al. 2010

Reproduction

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The luteal phase of the giant panda has been exclusively assessed by studying urinary hormone patterns in a very few individuals. To better understand hormonal dynamics of protracted progestagen excretion in this endangered species, we monitored hormonal metabolites in the fibrous faeces of multiple females in the USA and China. Giant pandas that were anoestrual during the breeding season excreted baseline progestagen throughout the year. In contrast, there were two distinctive periods when progestagen excretion increased in females that experienced behavioural oestrus, the first being modest, lasting for 61-122 days, and likely reflecting presumptive ovulation. This increase was far surpassed by a secondary rise in progestagen excretion associated with a rejuvenated luteal capacity or hormone production from an extra-gonadal source. The duration of this 'secondary' rise in progestagen excretion averaged w45 days and terminated in a decline to baseline coincident with parturition or the end of a non-parturient luteal interval. Data revealed that, even with a complex, biphasic progestagen profile, the longitudinal patterns produced by giant pandas were relatively consistent among animals and across years within individuals. However, progestagen excretion patterns throughout this period could not be used to discriminate among non-pregnant, pregnant or pseudopregnant states.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Unique biphasic progestagen profile in parturient and non-parturient giant pandas (Ailuropoda melanoleuca) as determined by faecal hormone monitoring

Kersey¹,

Wildt²,

Brown³

et al. 2010

Reproduction

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“…However, many morphological and molecular studies have recently revealed that affinities of the Pinnipedia lie within the suborder Caniformia of the order Carnivora, which includes Ursidae (bears) and Mustelidae (weasels, martens, etc.) [20].From the viewpoint of reproduction, delayed implantation occurs in most pinnipeds as it does in bears and martens [1,16,17]. Although the total pregnancy periods of ribbon seals and Steller sea lions last almost one year, their postimplantation periods (active pregnancy periods) are shorter due to delayed implantations [14].…”

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confidence: 99%

“…From the viewpoint of reproduction, delayed implantation occurs in most pinnipeds as it does in bears and martens [1,16,17]. Although the total pregnancy periods of ribbon seals and Steller sea lions last almost one year, their postimplantation periods (active pregnancy periods) are shorter due to delayed implantations [14].…”

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confidence: 99%

Immunohistochemical Localization of Steroidogenic Enzymes in the Corpus Luteum and the Placenta of the Ribbon Seal(Phoca fasciata) and Steller Sea Lion.

Ishinazaka

Suzuki

Yamamoto

et al. 2001

The Journal of Veterinary Medical Science

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ABSTRACT. To study the luteal and placental function of pinnipeds, we analyzed the localization of steroidogenic enzymes (P450scc, 3 β HSD and P450arom) in the corpus luteum and the placenta of ribbon seals (Phoca fasciata) and Steller sea lions (Eumetopias jubatus) immunohistochemically. P450scc and 3 β HSD were present in all luteal cells of both species. Almost all of the luteal cells were immunostained for P450arom, while P450scc and 3 β HSD were negatively immunostained in placentae and P450arom was present in the syncytiotrophoblast of placentae. These findings suggest that 1) corpora lutea of both species synthesize pregnenolone, progesterone and estrogen during the entire pregnancy period, and 2) like other terrestrial carnivores in the suborder Caniformia, placentae of both species do not have the capability for synthesizing progesterone in the latter half of active pregnancy period. KEY WORDS: corpus luteum, placenta, ribbon seal, Steller sea lion, steroidogenic enzyme.J. Vet. Med. Sci. 63(9): 955-959, 2001 Both the ribbon seal (Phoca fasciata) and the Steller sea lion (Eumetopias jubatus) are highly adapted for an aquatic lifestyle, and they are classified in the order Carnivora [13,20]. In the past, seals (family Phocidae), sea lions (family Otariidae) and walrus (family Odobenidae) were usually classified as a separate order, the Pinnipedia, or as a suborder of the order Carnivora. However, many morphological and molecular studies have recently revealed that affinities of the Pinnipedia lie within the suborder Caniformia of the order Carnivora, which includes Ursidae (bears) and Mustelidae (weasels, martens, etc.) [20].From the viewpoint of reproduction, delayed implantation occurs in most pinnipeds as it does in bears and martens [1,16,17]. Although the total pregnancy periods of ribbon seals and Steller sea lions last almost one year, their postimplantation periods (active pregnancy periods) are shorter due to delayed implantations [14]. Timing of implantation in ribbon seals is assumed to occur in August [2], although details are unknown. The attachment of blastocyst in Steller sea lions occurs in late September and October [19]. The peak of pupping of ribbon seals and Steller sea lions occurs early in April and early in June, respectively [3,19].In some terrestrial carnivorous animals, the corpus luteum is the most important source of progesterone during the entire gestation period [6,8,18,22,23]. In seals, however, it is not known whether the corpus luteum can synthesize progesterone in late pregnancy, or if the placenta replaces the corpus luteum as a principal source of progesterone, as occurs in sheep and humans [18]. The aim of this study is to clarify whether the corpus luteum and the placenta of ribbon seals and Steller sea lions in the latter half of an active pregnancy period are capable of steroidogenesis. MATERIALS AND METHODSOvaries and placentae were collected from 8 wild ribbon seals and 8 wild Steller sea lions. The animals were shot legally by hunters as part of nuisance contr...

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“…Previous studies showing involvement of melatonin in embryonic diapause have been described in carnivores (Mead 1989(Mead , 1993 and marsupials (McConnell & Hinds 1985, Oates et al 2004. Melatonin treatment was highly effective in lengthening the duration of the preimplantation period in mink and spotted skunk (Duby et al 1972, May & Mead 1986), while melatonin administration in marsupials terminates diapauses (Hinds & den Ottolander 1983, McConnell & TyndaleBiscoe 1985.…”

Section: Discussionmentioning

confidence: 97%

Melatonin regulates delayed embryonic development in the short-nosed fruit bat, Cynopterus sphinx

Banerjee

Meenakumari²,

Udin³

et al. 2009

Reproduction

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The aim of the present study was to evaluate the seasonal variation in serum melatonin levels and their relationship to the changes in the serum progesterone level, ovarian steroidogenesis, and embryonic development during two successive pregnancies of Cynopterus sphinx. Circulating melatonin concentrations showed two peaks; one coincided with the period of low progesterone synthesis and delayed embryonic development, whereas the second peak coincided with regressing corpus luteum. This finding suggests that increased serum melatonin level during November-December may be responsible for delayed embryonic development by suppressing progesterone synthesis. The study showed increased melatonin receptors (MTNR1A and MTNR1B) in the corpus luteum and in the utero-embryonic unit during the period of delayed embryonic development. The in vitro study showed that a high dose of melatonin suppressed progesterone synthesis, whereas a lower dose of melatonin increased progesterone synthesis by the ovary. The effects of melatonin on ovarian steroidogenesis are mediated through changes in the expression of peripheral-type benzodiazepine receptor, P450 side chain cleavage enzyme, and LH receptor proteins. This study further showed a suppressive impact of melatonin on the progesterone receptor (PGR) in the utero-embryonic unit; this effect might contribute to delayed embryonic development in C. sphinx. The results of the present study thus suggest that a high circulating melatonin level has a dual contribution in retarding embryonic development in C. sphinx by impairing progesterone synthesis as well as by inhibiting progesterone action by reducing expression of PGR in the utero-embryonic unit. Reproduction (2009) 138 935-944

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The Physiology and Evolution of Delayed Implantation in Carnivores

Cited by 46 publications

References 111 publications

Unique biphasic progestagen profile in parturient and non-parturient giant pandas (Ailuropoda melanoleuca) as determined by faecal hormone monitoring

Unique biphasic progestagen profile in parturient and non-parturient giant pandas (Ailuropoda melanoleuca) as determined by faecal hormone monitoring

Immunohistochemical Localization of Steroidogenic Enzymes in the Corpus Luteum and the Placenta of the Ribbon Seal(Phoca fasciata) and Steller Sea Lion.

Melatonin regulates delayed embryonic development in the short-nosed fruit bat, Cynopterus sphinx

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