Further Studies on the Radioimmunoassay of Gonadotropin-Releasing Hormone: Effect of Radioiodination, Antiserum and Unextracted Serum on Levels of Immunoreactivity in Serum<sup>1</sup>

Nett, Terry M.; Adams, Thomas E.

doi:10.1210/endo-101-4-1135

Cited by 126 publications

(46 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, the presence of only one peak of radioactivity after Page suggests the absence of a detectable diiodo-LRF contaminant ; this is confirmed by chromatographic analysis on silica gel. These conditions may be related to assay sensitivity (0.4 pg/tube), and are similar to the best procedures previously published (Jeffcoat, 1974 ;Nett and Adams, 1977 Sandow and Heptner (1973) and Shin and Howitt (1974). Furthermore, the present paper reports an hypothalamic content of 60 to 80 ng of LRF in the intact ram which is close to the values given for the ewe (Wheaton, 1976).…”

supporting

confidence: 88%

Reassessment of LRF radioimmunoassay in the plasma and hypothalamic extracts of rats and rams

Caraty¹,

Reviers²,

Pelletier³

et al. 1980

Reprod. Nutr. Dévelop.

View full text Add to dashboard Cite

The inhibition curves parallel to the synthetic LRF curve were obtained by diluting the crude hypothalamic extracts of rams and rats, and a good correlation (r = 0,997) with the Ramirez-McCann bioassay resulted, indicating that using radioimmunoassay to determine hypothalamic LRF content may be fruitful in studying hypothalamo-pituitary gonad interactions. The LRF content of rat and ovine hypothalami ranged from 2-8 to 20-80 ng of LRF, respectively.Introduction.

show abstract

supporting

confidence: 88%

Reassessment of LRF radioimmunoassay in the plasma and hypothalamic extracts of rats and rams

Caraty¹,

Reviers²,

Pelletier³

et al. 1980

Reprod. Nutr. Dévelop.

View full text Add to dashboard Cite

show abstract

“…The diluted plasma was placed in culture tubes with 20,000 cpm of 1251-LHRH (100 /11; approx. 1,500 Ci/mmol) and incubated overnight at 4 C. The radioiodinated LHRH used for binding was prepared by reacting 2.5 /~g LHRH with .5 mCi of 12sl8 and 4 /2g chloramine T. Monoiodinated LHRH was separated from the other reaction products by QAE Sephadex chromatography (Nett and Adams, 1977). Free and bound 12SI-LHRH were separated by the addition of 100 /A dextran-coated charcoal.…”

Section: Antibody Titers To Lhrh Antibody Titersmentioning

confidence: 99%

Effect of Active Immunization against LHRH or LH in Boars: Reproductive Consequences and Performance Traits

Falvo

Chandrashekar

Arthur

et al. 1986

Journal of Animal Science

View full text Add to dashboard Cite

Forty crossbred boars were equally divided into eight groups at birth. Four groups were immunized (200 ~g/boar) at 12 wk of age against either luteinizing hormone-releasing hormone (LHRH) conjugated to human serum globulin (LHRH-hSG) in complete Freund's adjuvant (CFA), LHRH-hSG in muramyldipeptide adjuvant (PEP), procine luteinizing hormone (LH) conjugated to hSG (pLH-hSG) in CFA or ovine LH (oLH) in CFA. Equal doses of boosters were given in either PEP or incomplete Freund's adjuvant (IFA) at 16 and 18 wk of age. Two groups of boars were immunized with either hSG + CFA or hSG + PEP (adjuvant controls). Two groups were castrated either at the time of weaning (castrate weaning) or at 16 wk when immunized boars were given their first booster injections (castrate booster). All pigs were slaughtered at 24 wk of age. Serum levels of LH and testosterone (T), LHRH or LH antibody titers, as well as testicular and accessory sex gland weights and histology were determined. By wk 16, LHRH antibody titers began to rise in those boars immunized against LHRH-hSG. Luteinizing hormone-releasing hormone antibody titers on wk 18, 20 and 22 were greater than those at wk 16. By 22 wk of age, LHRH-hSG boars had non-detectable plasma LH and T and reduced weights of testes and acessory sex glands. Boars immunized against oLH did not respond to treatment, whereas pLH-hSG boars showed a reduction in serum T levels and accessory sex gland weights. Immunization had no effect on average daily gain, hot carcass weights or loin eye area. Animals immunized against LHRH in CFA had increased lOth rib fat (P<.05) when compared with the castrated controls, adjuvant controls and the pLH-immunized boars. The incidence of boar taint was reduced (P<.05) in the LHRH-hSG and pLH-treated boars. We conclude that LHRH imrnunoneutralization resulted in castration-like carcass effects in boars but had no effect on performance characteristics, with the possible exception of backfat thickness. These data demonstrate for the first time that active immunization against LHRH is both feasible and practical as an alternative to surgical castration in boars.

show abstract

“…GnRH levels also appear to increase at the time of the proestrus surge in rats (7) and rhesus monkeys (8,9). These direct techniques of accessing information regarding the hypothalamic component of the preovulatory surge are clearly not feasible in the human and measurements of GnRH in the peripheral circulation do not accurately reflect hypothalamic GnRH secretion ifat all (10). Therefore, an understanding of the physiology of GnRH secretion and pituitary responsiveness to this releasing hormone in the human can only be achieved by combining a number of indirect approaches.…”

mentioning

confidence: 99%

Decreased release of gonadotropin-releasing hormone during the preovulatory midcycle luteinizing hormone surge in normal women.

Hall

Taylor²,

Rivier³

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

To investigate the contribution of hypothalamic gonadotropin-releasing hormone (GnRH) secretion to the midcyde gonadotropin surge in the human, the response of luteniZing hormone (LH) to competitive GnRH receptor blockade achieved by administration of a range of doses of a pure GnRH antagonist was used to provide a semiquantitative estimate of endogenous GnRH secretion. The LH response to 5, 15, 50, and 150 iag/kg s.c. of the NAL-GLU GnRH antagonist ',D-4CIPhe2,D-Pal3,Arg5,D-4-p-methoxybenzoyl-2-aminobutyric acid'6,D-Ala1O'GnRH, where 2Nal is 2-naphthylalanine, 4CIPhe is 4-chlorophenylalanine, and 3Pal is 3-pyridylabnine) was measured in normal women in the early and late follicular phases of the menstrual cycle, at the time of the midcycle LH surge and in the early luteal phase. LH decreased in a dose-response fashion after administration of the GnRH antagonist in aUi cycle phases (P < 0.0001 Direct measurements of GnRH in pituitary portal blood indicate that a surge of GnRH secretion is generally associated with spontaneous and sex steroid-induced gonadotropin surges in sheep (4-6). GnRH levels also appear to increase at the time of the proestrus surge in rats (7) and rhesus monkeys (8, 9). These direct techniques of accessing information regarding the hypothalamic component of the preovulatory surge are clearly not feasible in the human and measurements of GnRH in the peripheral circulation do not accurately reflect hypothalamic GnRH secretion ifat all (10). Therefore, an understanding of the physiology of GnRH secretion and pituitary responsiveness to this releasing hormone in the human can only be achieved by combining a number of indirect approaches. Monitoring of pulsatile LH secretion can provide insight into the frequency of GnRH secretory episodes (11) but does not permit estimates to be made ofthe amount of GnRH secreted. The dose of exogenous pulsatile GnRH required to mimic normal menstrual cycles and a normal midcycle surge in GnRH-deficient women (3) has been determined empirically, by comparison with "target"or reference ranges derived from studies in normal women, but does not provide information about potential changes in the actual quantity of endogenous GnRH secreted under various physiologic conditions in the intact human.A competitive receptor antagonist can be used to assess the relative amount of an unmeasurable endogenous ligand by determining the susceptibility of a marker of its action to specific blockade. This principle derives from quantitative theories of drug action (12) and has proven extremely useful in determination of opioid tone using the opiate receptor blocker, naloxone (13,14). We have applied an analogous approach to the assessment of the overall amount of GnRH secreted by using a GnRH antagonist that competitively blocks the GnRH receptor and LH secretion as the marker of GnRH action. The underlying assumption is that the amount ofGnRH present at a given time is directly proportional to the dose of GnRH antagonist required to inhibit LH secretion. 2Nal is 2-napht...

show abstract

Further Studies on the Radioimmunoassay of Gonadotropin-Releasing Hormone: Effect of Radioiodination, Antiserum and Unextracted Serum on Levels of Immunoreactivity in Serum¹

Cited by 126 publications

References 23 publications

Reassessment of LRF radioimmunoassay in the plasma and hypothalamic extracts of rats and rams

Reassessment of LRF radioimmunoassay in the plasma and hypothalamic extracts of rats and rams

Effect of Active Immunization against LHRH or LH in Boars: Reproductive Consequences and Performance Traits

Decreased release of gonadotropin-releasing hormone during the preovulatory midcycle luteinizing hormone surge in normal women.

Contact Info

Product

Resources

About

Further Studies on the Radioimmunoassay of Gonadotropin-Releasing Hormone: Effect of Radioiodination, Antiserum and Unextracted Serum on Levels of Immunoreactivity in Serum1

Cited by 126 publications

References 23 publications

Reassessment of LRF radioimmunoassay in the plasma and hypothalamic extracts of rats and rams

Reassessment of LRF radioimmunoassay in the plasma and hypothalamic extracts of rats and rams

Effect of Active Immunization against LHRH or LH in Boars: Reproductive Consequences and Performance Traits

Decreased release of gonadotropin-releasing hormone during the preovulatory midcycle luteinizing hormone surge in normal women.

Contact Info

Product

Resources

About

Further Studies on the Radioimmunoassay of Gonadotropin-Releasing Hormone: Effect of Radioiodination, Antiserum and Unextracted Serum on Levels of Immunoreactivity in Serum¹