Development and regression of the corpus luteum in grey seal (Halichoerus grypus) ovaries and its use in determining fertility rates

1984 ◽  
Vol 62 (6) ◽  
pp. 1095-1100 ◽  
Author(s):  
I. L. Boyd
Keyword(s):  
Corpus Luteum ◽  
Adult Female ◽  
Halichoerus Grypus ◽  
Embryonic Diapause ◽  
Grey Seal ◽  
Fertility Rates ◽  
Reproductive Condition ◽  
Plasma Progesterone ◽  
Blood Samples ◽  
Foetal Growth

Adult female grey seals were sampled at the Fame Islands at monthly intervals from November 1980 to October 1981. The distribution, size, and number of ovarian corpora were recorded in each case and blood samples were obtained for progesterone analysis. The concentration of plasma progesterone was about 6 ng/mL for most of gestation, including embryonic diapause, and rose to about 10 ng/mL during the final month. Progesterone declined sharply to less than 1 ng/mL at parturition. The size of the corpus luteum was constant throughout embryonic diapause, but after implantation it grew continuously until parturition. Following parturition, it regressed rapidly at first, forming a corpus albicans, and then more slowly, regression being arrested during the period of foetal growth of the following reproductive cycle. Most corpora albicantia had disappeared 1 year after their formation. Corpora albicantia may be useful indicators of reproductive history in grey seals, providing that allowance is made for the reproductive condition of females at the time of sampling and for several other possible errors which could arise. Retrospective calculation of reproductive statistics by more than 1 year using corpora albicantia is not valid for grey seals.

A note on the effect of melatonin feeding on the initiation of ovarian activity and on plasma prolactin levels in lactating and non-lactating red deer hinds

1985 ◽  
Vol 40 (3) ◽  
pp. 515-518 ◽  
Author(s):  
Rachel Nowak ◽  
R. N. Elmhirst ◽  
R. G. Rodway
Keyword(s):  
Detection Limit ◽  
Corpus Luteum ◽  
Red Deer ◽  
Inhibitory Effect ◽  
Ovarian Activity ◽  
Plasma Prolactin ◽  
Melatonin Treatment ◽  
Plasma Progesterone ◽  
Blood Samples

ABSTRACTMelatonin was fed daily at 14.00 h to eight non-lactating and six lactating hinds. Feeding was begun on 27 July 1983 (day 1) and continued until 21 September (day 57). Six non-lactating hinds were used as controls. Blood samples were taken about every 10 days from day 42 until day 73. Plasma progesterone and prolactin were determined by radioimmunoassay. Progesterone values of greater than 0·63 μg/1 were taken to indicate the presence of a corpus luteum and that the animal had ovulated. In the melatonintreated, non-lactating group seven of the eight hinds showed ovarian activity compared with two of the six controls (P < 0·01). None of the lactating hinds treated with melatonin showed evidence of ovarian activity. In both the lactating and non-lactating hinds treated with melatonin, prolactin levels were never greater than the detection limit of the assay (7·4 μg/l), while, in the control hinds mean prolactin levels were elevated on all but the last sampling day. It is, therefore, possible to induce early ovarian activity in non-lactating red deer hinds by feeding melatonin. However, although melatonin treatment similarly depressed plasma prolactin levels in both lactating and non-lactating hinds, it was unable to overcome the inhibitory effect of lactation on reproduction.

CORPUS LUTEUM ACTIVITY AND PROSTAGLANDIN LEVELS AFTER PARTURITION IN COWS WITH RETAINED FETAL MEMBRANES

1987 ◽  
Vol 67 (1) ◽  
pp. 21-26 ◽  
Author(s):  
PIERRE MATTON ◽  
VICTOR ADELAKOUN ◽  
JACQUES DUFOUR
Keyword(s):  
Key Words ◽  
Corpus Luteum ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Fetal Membranes ◽  
Plasma Progesterone ◽  
Blood Samples ◽  
Retained Placenta ◽  
Progesterone Production ◽  
Prostaglandin F

Previous results have shown that progesterone levels were higher on the day of parturition in cows with retained fetal membranes (RFM) than in cows with normal calving, suggesting incomplete lysis of the corpus luteum (CL). This experiment was performed to evaluate the activity of the CL and the level of 13,14-dihydro-15-keto prostaglandin F2α (PGFM) in RFM cows. Cows with RFM or those calving normally (NC) were ovariectomized 12–14 h after parturition. Blood samples were taken from the caudal and utero-ovarian veins. Slices of CL were incubated with or without human chorionic gonadotrophin (hCG) medium for 3 h. Plasma progesterone was higher in both the caudal and utero-ovarian veins of RFM cows than in those of NC cows (1.12 ± 0.25 vs. 0.62 ± 0.08 ng mL−1 and 2.4 ± 0.3 vs. 1.44 ± 0.33 ng mL−1, respectively). PGFM was also significantly higher in RFM cows (3.62 ± 0.19 vs. 2.55 ± 0.15 ng mL−1). Progesterone production by CL slices from both types of cows, incubated without hCG, was similar (65 ± 4.2 vs. 73 ± 5.1 μg g−1); with hCG, however, the progesterone production by the CL of RFM cows was 186.3 ± 10.7 μg g−1, 75.7 μg g−1 more than in CL of cows with normal calving. These results support the hypothesis of an incomplete luteolysis of the CL in RFM cows in spite of hieher levels of PGF2α. Key words: Corpus luteum activity, progesterone, prostaglandin, postpartum cows, retained placenta

scholarly journals INFLUENCE OF THYROTROPIN-RELEASING HORMONE (TRH) ON PLASMA PROGESTERONE AND PITUITARY HORMONE CONCENTRATIONS IN CATTLE

1975 ◽  
Vol 55 (4) ◽  
pp. 633-640 ◽  
Author(s):  
J. G. MANNS ◽  
H. D. HAFS ◽  
G. E. LAMMING
Keyword(s):  
Growth Hormone ◽  
Corpus Luteum ◽  
Prolactin Secretion ◽  
Thyrotropin Releasing Hormone ◽  
Saline Control ◽  
Pituitary Hormone ◽  
Corpora Lutea ◽  
Plasma Progesterone ◽  
Blood Samples ◽  
Releasing Hormone

Four Friesian heifers 14–16 mo of age were injected through jugular catheters six times per day (0600, 0900, 1200, 1500, 1800 and 2100 h) with 100 μg thyrotropin-releasing hormone or saline (control). TRH and saline treatment continued for 14 days beginning 1 day after a luteolytic dose of prostaglandin (PGF2α, 30 mg) which was given during diestrus. Blood samples were collected via the catheters at 0900 and 2100 h each day for progesterone prolactin and LH determinations and before and 10, 20, 30, 40 and 60 min after the 0600 and 2100 h TRH injections on the 1st, 7th and 13th days of treatment for growth hormone (GH) and prolactin analysis. After 14 days, heifers were injected with 10 mg PGF2α and changes in blood progesterone were measured for 24 h. There were two treatment periods; hence, each animal was subjected to both TRH and saline injections. Results support the following conclusions: (1) Prolactin secretion in response to TRH did not diminish with time. (2) Plasma progesterone of TRH-treated animals was lower (P < 0.05) from approximately day 5 of the cycle (estrus = day 0) until corpora lutea were destroyed with PGF2α; this provides no support for a luteotrophic role for prolactin. (3) Corpora lutea of all animals regressed after 10 mg PGF2α, suggesting that TRH had not increased the resistance of the corpus luteum to the luteolytic effects of PGF2α.

Embryology and foetal growth of the Grey seal, Halichoerus grypus

2009 ◽  
Vol 155 (4) ◽  
pp. 507-533 ◽  
Author(s):  
H. R. Hewer ◽  
K. M. Backhouse
Keyword(s):  
Halichoerus Grypus ◽  
Grey Seal ◽  
Foetal Growth

Utilizing next-generation sequencing to identify prey DNA in western North Atlantic grey seal Halichoerus grypus diet

2020 ◽  
Vol 655 ◽  
pp. 227-240
Author(s):  
KR Flanders ◽  
ZH Olson ◽  
KA Ono
Keyword(s):  
Next Generation Sequencing ◽  
Feeding Habits ◽  
Atlantic Menhaden ◽  
Halichoerus Grypus ◽  
Frequency Of Occurrence ◽  
Grey Seal ◽  
Next Generation ◽  
Significant Difference ◽  
Generation Sequencing ◽  
Seal Diet

Increasing grey seal Halichoerus grypus abundance in coastal New England is leading to social, political, economic, and ecological controversies. Central to these issues is the foraging ecology and diet composition of the seals. We studied grey seal feeding habits through next-generation sequencing of prey DNA using 16S amplicons from seal scat (n = 74) collected from a breeding colony on Monomoy Island in Massachusetts, USA, and report frequency of occurrence and relative read abundance. We also assigned seal sex to scat samples using a revised PCR assay. In contrast to current understanding of grey seal diet from hard parts and fatty acid analysis, we found no significant difference between male and female diet measured by alpha and beta diversity. Overall, we detected 24 prey groups, 18 of which resolved to species. Sand lance Ammodytes spp. were the most frequently consumed prey group, with a frequency of occurrence (FO) of 97.3%, consistent with previous studies, but Atlantic menhaden Brevoortia tyrannus, the second most frequently consumed species (FO = 60.8%), has not previously been documented in US grey seal diet. Our results suggest that a metabarcoding approach to seal food habits can yield important new ecological insights, but that traditional hard parts analysis does not underestimate consumption of Atlantic cod Gadus morhua (FO = 6.7%, Gadidae spp.) and salmon Salmo salar (FO = 0%), 2 particularly valuable species of concern.

PROGESTERONE IN THE HUMAN PERIPHERAL BLOOD IN THE PREOVULATORY PERIOD OF THE MENSTRUAL CYCLE

1967 ◽  
Vol 55 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Benno Runnebaum ◽  
Josef Zander
Keyword(s):  
Menstrual Cycle ◽  
Corpus Luteum ◽  
Peripheral Blood ◽  
Human Peripheral Blood ◽  
Progesterone Concentration ◽  
Plasma Progesterone ◽  
Progesterone Secretion ◽  
Graafian Follicle ◽  
The Mean ◽  
Mean Concentration

ABSTRACT Progesterone was determined and identified in human peripheral blood during the preovulatory period of the menstrual cycle, by combined isotope derivative and recrystallization analysis. The mean concentration of progesterone in 1.095 ml of plasma obtained 9 days before ovulation was 0.084 μg/100 ml. However, the mean concentration of progesterone in 1.122 ml of plasma obtained 4 days before ovulation was 0.279 μg/100 ml. These data demonstrate a source of progesterone secretion other than the corpus luteum. The higher plasma-progesterone concentration 4 days before ovulation may indicate progesterone secretion of the ripening Graafian follicle of the ovary.

Pattern of plasma progesterone, oestradiol-17β, luteinizing hormone and androgen in non-pregnant buffalo (Bubalus bubalis)

1982 ◽  
Vol 100 (2) ◽  
pp. 279-284 ◽  
Author(s):  
R. C. Arora ◽  
R. S. Pandey
Keyword(s):  
Luteinizing Hormone ◽  
Peak Level ◽  
Systemic Circulation ◽  
Bubalus Bubalis ◽  
High Concentration ◽  
Plasma Progesterone ◽  
Blood Samples ◽  
Androgen Level ◽  
The Mean ◽  
Low Levels

Abstract. Domestic buffaloes were used to characterize the pattern of progesterone, oestradiol-17β, LH and androgen in the systemic circulation following infertile insemination. Concentrations of hormones were measured by RIA in blood samples collected daily or at alternate days following insemination. The concentration of progesterone was lowest on the day of insemination, and increased significantly to a peak level of 4.00 ± 0.60 ng/ml by day 13 post insemination. After day 17, it declined significantly (P < 0.01) to reach low levels by day 21. The concentration of oestradiol-17β was high at the time of insemination and declined significantly (P < 0.01) by day 2 after insemination. It was maintained around the basal level till day 18 with minor peaks in between this period. It again rose significantly (P < 0.01) at subsequent oestrus. The mean level of LH was highest at the time of insemination, and declined significantly (P < 0.01) by day 1 post insemination. It did not vary appreciably till the animal returned to oestrus. The oestrous value of LH and progesterone were negatively correlated (r = −0.77). The androgen level was observed to be high at insemination in 3 out of 5 animals, but the overall pattern of this steroid was inconsistent during the period studied. A high concentration of androgen was recorded in all the animals from day 2–5 before the onset of oestrus.

Predation by Sharks on the Grey Seal (Halichoerus grypus) in Eastern Canada

1983 ◽  
Vol 40 (3) ◽  
pp. 267-271 ◽  
Author(s):  
Paul Brodie ◽  
Brian Beck
Keyword(s):  
Key Words ◽  
Population Size ◽  
Halichoerus Grypus ◽  
Longline Fishery ◽  
Grey Seal ◽  
Eastern Canada ◽  
The Past ◽  
Harbour Seals ◽  
Commercially Important ◽  
Important Fish

The increase in population size of the grey seal (Halichoerus grypus) off eastern Canada over the past 20 yr may be attributed to a decrease in shark stocks, their supposed predators. Reduction of the shark population is presumed to have resulted from a directed longline fishery and, of greater significance, from a change in the fishery for swordfish (Xiphias gladius) from selective harpooning to pelagic longlining, which has produced a large bycatch of sharks. The resulting enhanced survival of grey seals is reflected in greater infestation of commercially important fish species by the codworm (Phocanema decipiens).Key words: grey seals, harbour seals, sharks, swordfish, codworm, predation, fisheries

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