Effects of naloxone and electroacupuncture treatment on plasma concentrations of LH in sheep

1984 ◽  
Vol 101 (1) ◽  
pp. 75-80 ◽  
Author(s):  
P. V. Malven ◽  
D. F. B. Bossut ◽  
M. A. Diekman
Keyword(s):  
Breeding Season ◽  
Luteal Phase ◽  
Plasma Concentrations ◽  
Opioid Antagonist ◽  
Similar Treatment ◽  
Plasma Progesterone ◽  
Electroacupuncture Treatment

ABSTRACT Mature ewes were injected intravenously with the opioid antagonist naloxone (1·1 mg/kg) during the breeding season. Ewes with luteal phase concentrations of plasma progesterone responded with a significant (P <0·05) increase in plasma LH 14–23 min after naloxone injection. In contrast, non-luteal ewes with low plasma progesterone did not respond to injection of naloxone with an LH increase. Similar treatment of castrated males (wethers) with this dosage of naloxone failed to increase plasma LH. Electroacupuncture (EA) treatment of luteal phase ewes prevented the ability of exogenous naloxone to increase plasma LH. Treatment of wethers by EA decreased significantly (P <0·01) their high basal concentrations of plasma LH, but similar EA treatment of intact ewes did not change their low basal concentrations of LH. J. Endocr. (1984) 101, 75–80

Seasonal and steroid-dependent effects on the modulation of LH secretion in the ewe by intracerebroventricularly administered β-endorphin or naloxone

1989 ◽  
Vol 122 (2) ◽  
pp. 509-517 ◽  
Author(s):  
R. J. E. Horton ◽  
H. Francis ◽  
I. J. Clarke
Keyword(s):  
Breeding Season ◽  
Luteal Phase ◽  
Pulse Frequency ◽  
Opioid Peptide ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Opioid Antagonist ◽  
Endogenous Opioid ◽  
Endogenous Opioid Peptide ◽  
Lh Secretion

ABSTRACT The natural opioid ligand, β-endorphin, and the opioid antagonist, naloxone, were administered intracerebroventricularly (i.c.v.) to evaluate effects on LH secretion in ovariectomized ewes and in ovariectomized ewes treated with oestradiol-17β plus progesterone either during the breeding season or the anoestrous season. Ovary-intact ewes were also studied during the follicular phase of the oestrous cycle. Jugular blood samples were taken at 10-min intervals for 8 h and either saline (20–50 μl), 100 μg naloxone or 10 μg β-endorphin were injected i.c.v. after 4 h. In addition, luteal phase ewes were injected i.c.v. with 25 μg β-endorphin(1–27), a purported endogenous opioid antagonist. In ovariectomized ewes, irrespective of season, saline and naloxone did not affect LH secretion, but β-endorphin decreased the plasma LH concentrations, by reducing LH pulse frequency. The effect of β-endorphin was blocked by administering naloxone 30 min beforehand. Treating ovariectomized ewes with oestradiol-17β plus progesterone during the breeding season reduced plasma LH concentrations from 6–8 μg/l to less than 1 μg/l. In these ewes, saline did not alter LH secretion, but naloxone increased LH pulse frequency and the plasma concentrations of LH within 15–20 min. During anoestrus, the combination of oestradiol-17β plus progesterone to ovariectomized ewes reduced the plasma LH concentrations from 3–5 μg/l to undetectable levels, and neither saline nor naloxone affected LH secretion. During the follicular phase of the oestrous cycle, naloxone enhanced LH pulse frequency, which resulted in increased plasma LH concentrations; saline had no effect. In these sheep, β-endorphin decreased LH pulse frequency and the mean concentrations of LH, and this effect was prevented by the previous administration of naloxone. The i.c.v. administration of β-endorphin(1–27) to luteal phase ewes did not affect LH secretion. These data demonstrate the ability of a naturally occurring opioid peptide to inhibit LH secretion in ewes during the breeding and non-breeding seasons, irrespective of the gonadal steroid background. In contrast, whilst the gonadal steroids suppress LH secretion in ovariectomized ewes during both seasons, they only appear to activate endogenous opioid peptide (EOP)-mediated inhibition of LH secretion during the breeding season. Furthermore, these data support the notion that LH secretion in ovariectomized ewes is not normally under the control of EOP, so that naloxone has no effect. Journal of Endocrinology (1989) 122, 509–517

Effects of immunization against recombinant bovine inhibin α subunit on circulating concentrations of gonadotrophins in ewes

1989 ◽  
Vol 120 (1) ◽  
pp. 59-65 ◽  
Author(s):  
J. K. Findlay ◽  
B. Doughton ◽  
D. M. Robertson ◽  
R. G. Forage
Keyword(s):  
Breeding Season ◽  
Untreated Control ◽  
Luteal Phase ◽  
Plasma Concentrations ◽  
Follicular Phase ◽  
Ovulation Rate ◽  
Α Subunit ◽  
Keyhole Limpet Haemocyanin ◽  
Fourfold Increase ◽  
Breeding Seasons

ABSTRACT Immunization of ewes against a pure recombinant preparation of the α subunit of bovine inhibin (α-bI) resulted in a three- to fourfold increase in ovulation rate, associated with antibodies in plasma recognizing pure native 31 kDa inhibin. The aim of this study was to examine the effects of this immunization on basal and GnRH-stimulated plasma concentrations of FSH and LH in ewes during the anoestrous and breeding seasons. The groups were untreated control ewes (n = 5), control ewes treated with keyhole limpet haemocyanin (KLH alone, n = 4), ewes treated with α-bI alone (n = 4) and α-bI–KLH conjugate-treated ewes (n = 3). There were no effects of immunization on basal FSH or LH in anoestrous ewes, despite the presence of antibodies recognizing 31 kDa inhibin. In the breeding season, immunization against α-bI resulted in increased basal (follicular phase, P < 0·1; luteal phase P < 0·05) and GnRH-stimulated (follicular phase only, P < 0·001) release of FSH, but not LH. The data are compatible with the hypotheses that the increase in ovulation rate in immunized ewes is due to an increase in circulating FSH concentrations and that inhibin may only have a major peripheral influence on FSH in sheep during the breeding season. Journal of Endocrinology (1989) 120, 59–65

Peripheral plasma progesterone concentrations in pregnant and non-pregnant greyheaded flying-foxes (Pteropus poliocephalus) and little red flying-foxes (P. scapulatus)

1995 ◽  
Vol 7 (5) ◽  
pp. 1163 ◽  
Author(s):  
PA Towers ◽  
L Martin
Keyword(s):  
Breeding Season ◽  
Plasma Concentrations ◽  
Late Pregnancy ◽  
Corpora Lutea ◽  
Flying Foxes ◽  
Plasma Progesterone ◽  
Peripheral Plasma ◽  
Pteropus Poliocephalus ◽  
In The Wild ◽  
Gas Chromatography Mass Spectroscopy

Blood was collected from breeding-season and pregnant P. poliocephalus females shot in the wild and from captive pregnant and ovariectomized P. poliocephalus and P. scapulatus females. Peripheral plasma progesterone concentrations measured by radioimmunoassay were similar to those obtained by gas chromatography-mass spectroscopy: in intact non-pregnant P. poliocephalus females without corpora lutea (CLs) values ranged from 2 to 30 ng mL-1; after ovariectomy, they ranged from 1 to 85 ng mL-1. A significant source of progesterone in these bats may be the adrenal. In P. poliocephalus, peripheral plasma progesterone concentrations showed relatively little change over the breeding season or in early pregnancy when a CL formed, but increased from mid pregnancy to reach 200-800 ng mL-1 in late pregnancy. A mid-pregnancy ovary with CL contained 2.80 ng progesterone whereas the contralateral ovary contained 0.13 ng. Overall, CL size decreased during pregnancy and was negatively correlated with plasma progesterone concentrations. In late pregnancy, the main source of progesterone appears to be the placenta; plasma concentrations increase with placental growth and are significantly correlated with placental weight, and placentas contain 4-8 micrograms progesterone g-1. There was no evidence that progesterone concentrations fall before parturition. Limited observations indicated that peripheral progesterone concentrations follow similar patterns in P. scapulatus.

PLASMA CONCENTRATIONS OF LUTEINIZING HORMONE, FOLLICLE-STIMULATING HORMONE AND PROGESTERONE DURING THE BREEDING SEASON IN EWES IMMUNIZED AGAINST ANDROSTENEDIONE OR TESTOSTERONE

1979 ◽  
Vol 81 (3) ◽  
pp. 249-259 ◽  
Author(s):  
N. D. MARTENSZ ◽  
R. J. SCARAMUZZI
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Breeding Season ◽  
Bovine Serum ◽  
Luteal Phase ◽  
Follicle Stimulating Hormone ◽  
Plasma Concentrations ◽  
Biologically Active ◽  
Active Fraction ◽  
Lh Secretion

Levels of plasma LH, FSH and progesterone during the breeding season were measured by radioimmunoassay in control ewes and ewes actively immunized against androstenedione-11α-hemisuccinyl–bovine serum albumin or testosterone-3(O-carboxymethyl)oxime–bovine serum albumin. Immunization against androstenedione resulted in normal oestrous cycles with raised plasma LH and progesterone levels and a reduction in the concentration of FSH during the luteal phase. It is tentatively suggested that androstenedione, or its metabolites, could modify the oestrogenic control of LH secretion and facilitate the release of FSH in the ewe. Immunization against testosterone prevented oestrus and resulted in markedly increased levels of LH without alteration of the FSH concentration. Since evidence of increased binding of oestradiol-17β was found in the ewes immunized against testosterone, these results cannot be attributed solely to a reduction in the biologically active fraction of testosterone.

Studies of the oestrous cycle, oestrus and pregnancy in the koala (Phascolarctos cinereus)

Reproduction ◽  
2000 ◽  
pp. 49-57 ◽  
Author(s):  
SD Johnston ◽  
MR McGowan ◽  
P O'Callaghan ◽  
R Cox ◽  
V Nicolson
Keyword(s):  
Luteal Phase ◽  
Post Partum ◽  
Plasma Concentrations ◽  
External Genitalia ◽  
Oestrous Cycle ◽  
Phascolarctos Cinereus ◽  
Pregnant Females ◽  
Peripheral Plasma ◽  
The Mean ◽  
High Concentrations

As an integral part of the development of an artificial insemination programme in the captive koala, female reproductive physiology and behaviour were studied. The oestrous cycle in non-mated and mated koalas was characterized by means of behavioural oestrus, morphology of external genitalia and changes in the peripheral plasma concentrations of oestradiol and progestogen. The mean (+/- SEM) duration of the non-mated oestrous cycle and duration of oestrus in 12 koalas was 32.9 +/- 1.1 (n = 22) and 10.3 +/- 0.9 (n = 24) days, respectively. Although the commencement of oestrous behaviour was associated with increasing or high concentrations of oestradiol, there were no consistent changes in the morphology or appearance of the clitoris, pericloacal region, pouch or mammary teats that could be used to characterize the non-mated cycle. As progestogen concentrations remained at basal values throughout the interoestrous period, non-mated cycles were considered non-luteal and presumed anovulatory. After mating of the 12 koalas, six females gave birth with a mean (+/- SEM) gestation of 34.8 +/- 0.3 days, whereas the remaining six non-parturient females returned to oestrus 49.5 +/- 1. 0 days later. After mating, oestrous behaviour ceased and the progestogen profile showed a significant increase in both pregnant and non-parturient females, indicating that a luteal phase had been induced by the physical act of mating. Progestogen concentrations throughout the luteal phase of the pregnant females were significantly higher than those of non-parturient females. Parturition was associated with a decreasing concentration of progestogen, which was increased above that of basal concentrations until 7 days post partum.

A note on attainment of puberty of september-born early-maturing ewe lambs in relation to level of nutrition

1991 ◽  
Vol 53 (3) ◽  
pp. 407-409 ◽  
Author(s):  
F. Forcada ◽  
J. A. Abecia ◽  
L. Zarazaga
Keyword(s):  
Sexual Activity ◽  
Breeding Season ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Plasma Progesterone ◽  
Ewe Lambs ◽  
Early Maturing ◽  
Age At Puberty

The attainment of puberty in September-born early-maturing ewe lambs was studied at Zaragoza (latitude 41° 40' N). Thirty twin Salz females were allocated to two groups receiving two nutrition levels after 3 months of age: high (500 g/day lucerne hay and 500 g/day concentrate) (H) and low (500 g/ day lucerne hay) (L). Oestrus was detected daily by aproned rams. Corpora lutea were counted after oestrus and plasma progesterone levels monitored each week.In the first breeding season (January to February) the percentage of females showing sexual activity (silent emulation or oestrus and ovulation) was higher in the H compared with the L group (67 and 20%; P < 0/05). Nonpubertal oestrus before the main breeding season was detected in 67% of animals. In the main breeding season and for H and L groups respectively, percentage of females showing silent ovulation before puberty was 67 and 33% and mean age at puberty extended to 319 (s.e. 4-8) and 314 (s.e. 3·7) days. Ovulation rate at puberty was 1·73 (s.e. 0·13) and 1·33 (s.e. 0·15) respectively (P < 0·05).

scholarly journals Ovarian follicular dynamic and plasma progesterone concentration in Alpine goats on the breeding season

2018 ◽  
Vol 70 (6) ◽  
pp. 2017-2022 ◽  
Author(s):  
N.G. Alves ◽  
C.A.A. Torres ◽  
J.D. Guimarães ◽  
E.A. Moraes ◽  
P.B. Costa ◽  
...  
Keyword(s):  
Breeding Season ◽  
Progesterone Concentration ◽  
Plasma Progesterone

PLASMA PROLACTIN AND PROGESTERONE RESPONSES TO MATING ARE ALTERED IN AGED RATS

1981 ◽  
Vol 90 (2) ◽  
pp. 179-191 ◽  
Author(s):  
S. HENDRICKS ◽  
C. A. BLAKE
Keyword(s):  
Plasma Concentrations ◽  
External Jugular Vein ◽  
Female Rats ◽  
Plasma Prolactin ◽  
Aged Rats ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Plasma Progesterone ◽  
The One ◽  
The Right

The effects of varying amounts of copulatory stimulation on patterns of plasma concentrations of prolactin and progesterone were evaluated in 3- and 12-month-old female rats. The 12-month-old group included rats which still exhibited oestrous cycles and rats in persistent vaginal oestrus (PVO). The extent of copulatory stimulation was defined by the number of intromissions received during mating: ≤5,15 or > 50. Blood samples were drawn over the 8 days after mating through a cannula inserted into the right external jugular vein. Plasma from the samples was assayed for prolactin and progesterone. In aged but still cyclic rats, pregnancy rates were positively correlated with the number of intromissions received during mating. Only one rat in PVO became pregnant. All animals which became pregnant and rats in PVO which, after mating, exhibited a disruption of the pattern of PVO, showed the nocturnal surge of plasma prolactin characteristic of pregnant and pseudopregnant rats. While these surges persisted until day 8 after mating in pregnant animals, they were absent by this time in the rats in PVO. Prolactin surges were present in some but not all of the aged rats which did not become pregnant. Progesterone concentrations were raised in all pregnant animals except the one pregnant rat in PVO and, while not related to the number of intromissions, concentrations were higher 8 days after mating in young compared with those in aged pregnant rats. Plasma progesterone was low in rats in PVO regardless of disruption of the pattern of PVO. We have concluded that the failure of limited copulatory stimulation to induce pregnancy in older rats results, at least in part, from its failure to initiate nocturnal prolactin surges. Nevertheless, our data suggest that matings which are not experimentally limited should provide ample stimulation to establish such surges. Although reduced plasma concentrations of prolactin and progesterone at pro-oestrus and reduced plasma progesterone through part of gestation may contribute to decreasing fertility in aged rats, other unidentified factors appear to be involved in mediating the capacity of extensive copulatory stimulation to induce pregnancy in these animals.

scholarly journals Induction of fertility and pregnancy in the anœstrous ferret

1934 ◽  
Vol 115 (795) ◽  
pp. 410-421 ◽  
Keyword(s):  
Breeding Season ◽  
Anterior Lobe ◽  
Similar Treatment

Bissonnett (1932) was able to induce complete œstrus in three female ferrets by evening illumination from October 12 onwards, but similar treatment of a male from October 12 to December 22 failed to carry spermatogenesis beyond the spermatocyte stage. Mating, therefore, resulted only in pseudopreganancy. In a second series of animals illuminated from December 7 onwards, spermatorgenesis was secured during February and a litter was born on April 11 (Bissonnette, 1933). The normal untreated male, however, usually becomes fertile during February (Allanson, 1932) and the first litters of the season may be born early in April, so that Bissonnette cannot be said to have induced fertility outside the limits of the normal breeding season. Bissonnette’s failure to bring about premature spermatogenesis, though involving one animal only, suggested that the male was much more refractory than the female, especially since anterior lobe extracts and urine of pregnancy extracts readily cause ovulation in the anœstrous ovary (Hill and Parkes, 1930), while such extracts cause little reaction in the quiescent winter testis. It seemed, however, that a combination of additional light and gonad-stimulating extracts might be effective, and the present paper records experiments carried out on these lines, as a result of which pregnancy was induced in light-treated females well outside the limits of the normal breeding season.

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