LUTEOLYTIC ACTION OF PROSTAGLANDINS IN SWINE AND THE EFFECTS OF CLOPROSTENOL ON LUTEINIZING HORMONE RECEPTORS AND MEMBRANE STRUCTURE OF PORCINE CORPORA LUTEA

The luteolytic action of prostaglandin F2α (PGF2α), 15-keto-PGF2α, 15-methyl-PGF2α, and cloprostenol was evaluated in cycling gilts and sows after intramuscular injection on day 13 of the estrous cycle. Only cloprostenol significantly shortened the mean cycle length (18.5 vs. 20.3 d, P < 0.05). Cloprostenol also caused a more rapid decline in serum progesterone concentrations than did the other prostaglandins. Serum concentrations of the prostaglandin metabolite 13,14-dihydro-15-keto-PGF2α (PGFM), showed rapid transitory peaks after PGF2α or 15-keto-PGF2α and a lower, later rise after cloprostenol. A second experiment examined luteal luteinizing hormone (LH) receptors and luteal membrane ultrastructure during the estrous cycle and pregnancy and the effect of cloprostenol on these parameters during the estrous cycle. The number of unoccupied luteal LH receptors, as measured by specific 125I-hCG binding, dropped significantly from mid to late pregnancy and from mid to late cycle. Cloprostenol lowered serum progesterone concentrations but did not affect hCG binding. X-ray diffraction showed no correlation of gel or liquid-crystalline phase lipids in luteal microsomes with the stage of the estrous cycle or pregnancy or cloprostenol treatment. Key words: Swine, luteolysis, estrous cycle, prostaglandins, luteal LH receptors

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PROGESTERONE AND LUTEINIZING HORMONE CONCENTRATION IN SERUM OF PREGNANT GILTS ON DIFFERENT LEVELS OF FEED CONSUMPTION

Canadian Journal of Animal Science ◽

10.4141/cjas80-103 ◽

1980 ◽

Vol 60 (4) ◽

pp. 877-884 ◽

Cited By ~ 22

Author(s):

G. W. DYCK ◽

W. M. PALMER ◽

S. SIMARAKS

Keyword(s):

Luteinizing Hormone ◽

Feed Consumption ◽

Blood Collection ◽

Corpora Lutea ◽

Serum Progesterone ◽

Treatment Groups ◽

Fetal Survival ◽

Serum Lh ◽

Luteinizing Hormone Concentration ◽

Collection Period

Blood serum progesterone (P) and luteinizing hormone (LH) were determined in 31 Lacombe gilts at a 3- to 4-day interval from 10 to 56 days of pregnancy. They were fed 1.50 (L), 2.25 (M) or 3.00 (H) kg of a 16% protein diet/day and had average daily gains of 0.16 ± 0.02 (SE), 0.36 ± 0.02 and 0.60 ± 0.02 kg/day, respectively. All gilts were slaughtered between 59 and 61 days of pregnancy. The treatments had no effect on the number of corpora lutea (13.9 ± 0.4 CL), number of fetuses (10.8 ± 0.6), fetal survival (78.3 ± 3.7%) or mean fetal weight (122 ± 3 g). The gilts on the H level of feeding had heavier (P < 0.05) ovaries (18.4 ± 0.8 g) than those of the L (15.6 ± 0.7 g) or M (15.6 ± 0.8 g) treatment groups. Serum P concentration declined during the blood collection period (b = −0.12, −0.06 and −0.09 for the L, M and H groups, respectively). Serum P concentrations also were different (P < 0.01) for each treatment group (L, 16.7 ± 0.3; M, 13.8 ± 0.03; and H, 11.8 ± 0.3 ng/mL). The serum LH concentration was greater (P < 0.05) for the M gilts (0.63 ± 0.05 ng/mL) than for the L (0.37 ± 0.04 ng/mL) or H (0.47 ± 0.05 ng/mL) gilts. Significant correlations were observed among the number of fetuses, number of CL, ovarian weight and P for the L gilts, and the number of fetuses and CL for the M gilts. These results suggest that growth rate is a major contributor to differences in blood P and LH concentrations during pregnancy and that the animal adjusts its P and LH production to its specific requirements for the maintenance of pregnancy.

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Pituitary and Ovarian Luteinizing Hormone Releasing Hormone Receptors During the Estrous Cycle, Pregnancy and Lactation in the Rat12

Biology of Reproduction ◽

10.1095/biolreprod27.2.316 ◽

1982 ◽

Vol 27 (2) ◽

pp. 316-319 ◽

Cited By ~ 7

Author(s):

J. J. Reeves ◽

G. K. Tarnavsky ◽

T. Platt

Keyword(s):

Luteinizing Hormone ◽

Estrous Cycle ◽

Hormone Receptors ◽

Luteinizing Hormone Releasing Hormone ◽

Releasing Hormone ◽

Pregnancy And Lactation

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CONCENTRATIONS OF LUTEINIZING HORMONE, OESTRADIOL-17β AND PROGESTERONE IN THE PLASMA OF HEIFERS TREATED TO INDUCE SUPEROVULATION

Journal of Endocrinology ◽

10.1677/joe.0.0840425 ◽

1980 ◽

Vol 84 (3) ◽

pp. 425-437 ◽

Cited By ~ 54

Author(s):

J. SAUMANDE

Keyword(s):

Luteinizing Hormone ◽

Plasma Levels ◽

Corpora Lutea ◽

Prostaglandin F ◽

Pregnant Mare Serum Gonadotrophin

Concentrations of luteinizing hormone (LH), oestradiol-17β and progesterone were studied in 14 heifers treated with pregnant mare serum gonadotrophin (PMSG) and an analogue of prostaglandin F2α (PGF2α) 48 h later to induce superovulation. Plasma levels of oestradiol-17β before ovulation and of progesterone after ovulation were related to the number of ovulations but the concentrations of LH were not so related; however, hormone concentrations at the time of injection of PMSG could not be used to predict the rate of ovulation. The injected gonadotrophin also appeared to affect folliculogenesis after ovulation and this may explain the presence of large follicles in the ovary when the corpora lutea were counted. It was possible to demonstrate by analysis of plasma levels of hormones that few non-superovulated animals were really insensitive to PMSG.

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THE PERSISTENCE OF PROGESTERONE SECRETION IN PREGNANT RATS AFTER HYPOPHYSECTOMY AND HYSTERECTOMY: A COMPARISON WITH PSEUDOPREGNANT, DECIDUOMATABEARING PSEUDOPREGNANT, AND LACTATING RATS

Journal of Endocrinology ◽

10.1677/joe.0.0570063 ◽

1973 ◽

Vol 57 (1) ◽

pp. 63-74 ◽

Cited By ~ 16

Author(s):

I. ROTHCHILD ◽

R. B. BILLIAR ◽

I. T. KLINE ◽

G. PEPE

Keyword(s):

Luteinizing Hormone ◽

Clearance Rate ◽

Progesterone Level ◽

Corpora Lutea ◽

Metabolic Clearance ◽

Metabolic Clearance Rate ◽

Serum Progesterone ◽

Pregnant Rats ◽

Oestrogen Treatment ◽

Progesterone Secretion

SUMMARY To test the hypothesis of Raj & Moudgal (1970) that luteinizing hormone (LH) is the essential luteotrophin during pregnancy in the rat, pregnant rats were hypophysectomized and hysterectomized on either day 12 or day 15 of pregnancy, and the changes in peripheral serum progesterone level measured. The serum progesterone level remained at approximately the day-12 value for 3 days after hypophysectomy and hysterectomy on day 12, but fell drastically and remained low after the same operation on day 15, or in pseudopregnant rats operated on on day 12, or after removal of the ovaries from pregnant rats on day 12. Oestrogen treatment increased the serum progesterone level slightly in the pregnant rats after hypophysectomy and hysterectomy, but not after ovariectomy; it had no effect in the pseudopregnant rats, with or without deciduomata, or in lactating rats nursing litters of seven to nine pups. The corpora lutea stopped growing or slowly regressed soon after hypophysectomy—hysterectomy in all except the pregnant rats operated on on day 12 and treated with oestrogen, and in these growth was very slight. The luteal content of progesterone did not change for 3 days after hypophysectomy—hysterectomy on day 12 of pregnancy, and fell slightly thereafter. The metabolic clearance rate of progesterone was not significantly changed by hypophysectomy—hysterectomy. It thus appears that true secretion of progesterone continues in pregnant rats for about 3 days after day 12 in the absence of the pituitary and placentas, but at a much lower rate than that found in intact, or in day-12 hypophysectomized pregnant rats (Pepe & Rothchild, 1972a). The placental luteotrophin thus seems to increase the rate of progesterone secretion in the absence of LH. The results do not seem to fit with the hypothesis that LH is essential for progesterone secretion.

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