Levels of Luteinizing Hormone, Estradiol and Progesterone in Serum During the Estrous Cycle and Pregnancy in the Beagle Bitch

Nett, T. M.; Akbar, A. M.; Phemister, Robert D.; Holst, P. A.; Reichert, Leo E.; Niswender, Gordon D.

doi:10.3181/00379727-148-38491

Cited by 114 publications

(69 citation statements)

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“…Plasma LH concentration was measured by a heterologous RIA described previously by Nett et al [30], with a few modifications. A rabbit antiserum raised against ovine LH (CSU-204, kindly supplied by G.D. Niswender, Colorado State University, CO, USA), radio-iodinated bovine LH-7981 as prepared for our bovine LH assay [31], and canine pituitary standard LER 1685-1 (a gift of Dr. L.E.…”

Section: Hormone Determinationsmentioning

confidence: 99%

Adenohypophyseal function in bitches treated with medroxyprogesterone acetate

Beijerink

Bhatti

Okkens

et al. 2007

Domestic Animal Endocrinology

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The aim of this study was to investigate the effects of treatment with medroxyprogesterone acetate (MPA) on canine adenohypophyseal function. Five Beagle bitches were treated with MPA (10 mg/kg, every 4 weeks) and their adenohypophyseal function was assessed in a combined adenohypophyseal function test. Four hypophysiotropic hormones (CRH, GHRH, GnRH, and TRH) were administered before and 2, 5, 8, and 11 months after the start of MPA treatment, and blood samples for determination of the plasma concentrations of ACTH, cortisol, GH, IGF-1, LH, FSH, prolactin, ␣-MSH, and TSH were collected at −15, 0, 5, 10, 20, 30, and 45 min after suprapituitary stimulation.MPA successfully prevented the occurrence of estrus, ovulation, and a subsequent luteal phase. MPA treatment did not affect basal and GnRH-induced plasma LH concentrations. The basal plasma FSH concentration was significantly higher at 2 months after the start of MPA treatment than before or at 5, 8, and 11 months after the start of treatment. The maximal FSH increment and the AUC for N.J. Beijerink et al. / Domestic Animal Endocrinology xxx (2006) xxx-xxxmonths of MPA treatment. Differences in mean basal plasma GH concentrations before and during treatment were not significant, but MPA treatment resulted in significantly elevated basal plasma IGF-1 concentrations at 8 and 11 months. MPA treatment did not affect basal and stimulated plasma ACTH concentrations, with the exception of a decreased AUC for ACTH at 11 months. In contrast, the maximal cortisol increment and the AUC for cortisol after suprapituitary stimulation were significantly lower during MPA treatment than prior to treatment. MPA treatment did not affect basal plasma concentrations of prolactin, TSH, and ␣-MSH, with the exception of slightly increased basal plasma TSH concentrations at 8 months of treatment. MPA treatment did not affect TRH-induced plasma concentrations of prolactin and TSH.In conclusion, the effects of chronic MPA treatment on adenohypophyseal function included increased FSH secretion, unaffected LH secretion, activation of the mammary GH-induced IGF-I secretion, slightly activated TSH secretion, suppression of the hypothalamic-pituitary-adrenocortical axis, and unaffected secretion of prolactin and ␣-MSH.

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Section: Hormone Determinationsmentioning

confidence: 99%

Adenohypophyseal function in bitches treated with medroxyprogesterone acetate

Beijerink

Bhatti

Okkens

et al. 2007

Domestic Animal Endocrinology

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“…LH concentrations were measured by means of a heterologous RIA using an ovine LH-antibody (GDN no. 15) and a canine LH-standard (LER 1685-1) [36,37]. The sensitivity of the assay was 200 pg ml À1 and was defined by the amount of canine LHstandard which significantly prevented binding of the radio-iodinated ovine LH to the LH-antiserum.…”

Section: Hormone Analysesmentioning

confidence: 99%

Effects of the dopamine agonist cabergoline on the pulsatile and TRH-induced secretion of prolactin, LH, and testosterone in male beagle dogs

Koch

Hoppen²,

Dieleman

et al. 2006

Theriogenology

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In the present study, the pulsatile serum profiles of prolactin, LH and testosterone were investigated in eight clinically healthy fertile male beagles of one to six years of age. Serum hormone concentrations were determined in blood samples collected at 15 min intervals over a period of 6 h before (control) and six days before the end of a four weeks treatment with the dopamine agonist cabergoline (5 mg kg À1 bodyweight/day). In addition, the effect of cabergoline administration was investigated on thyrotropin-releasing hormone (TRH)-induced changes in the serum concentrations of these hormones.In all eight dogs, the serum prolactin concentrations (mean 3.0 AE 0.3 ng ml À1 ) were on a relatively constant level not showing any pulsatility, while the secretion patterns of LH and testosterone were characterised by several hormone pulses. Cabergoline administration caused a minor but significant reduction of the mean prolactin concentration (2.9 AE 0.2 ng ml À1 , p < 0.05) and did not affect the secretion of LH (mean 4.6 AE 1.3 ng ml À1 versus 4.4 AE 1.7 ng ml À1 ) or testosterone (2.5 AE 0.9 ng ml À1 versus 2.4 AE 1.2 ng ml À1 ). Under control conditions, a significant prolactin release was induced by intravenous TRH administration (before TRH: 3.8 AE 0.9 ng ml À1 ,

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“…Plasma LH concentrations were determined with a heterologous RIA as described previously by Nett et al (1975). A rabbit antiserum raised against ovine LH (CSU-204; kindly supplied by G.D. Niswender, Colorado State University, USA), radioiodinated NIA-MDD-bLH-4, and canine pituitary standard LER 1985-1 (a gift from Dr. L.E.…”

Section: Hormone Determinationmentioning

confidence: 99%

Effects of growth hormone secretagogues on the release of adenohypophyseal hormones in young and old healthy dogs

Bhatti

Duchateau

Ham

et al. 2006

The Veterinary Journal

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The effects of three growth hormone secretagogues (GHSs), ghrelin, growth hormone-releasing peptide-6 (GHRP-6), and growth hormone-releasing hormone (GHRH), on the release of adenohypophyseal hormones, growth hormone (GH), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), luteinising hormone (LH), prolactin (PRL) and on cortisol were investigated in young and old healthy Beagle dogs.Ghrelin proved to be the most potent GHS in young dogs, whereas in old dogs GHRH administration was associated with the highest plasma GH concentrations. The mean plasma GH response after administration of ghrelin was significantly lower in the old dogs compared with the young dogs. The mean plasma GH concentration after GHRH and GHRP-6 administration was lower in the old dogs compared with the young dogs, but this difference did not reach statistical significance. In both age groups, the GHSs were specific for GH release as they did not cause significant elevations in the plasma concentrations of ACTH, cortisol, TSH, LH, and PRL. It is concluded that in young dogs, ghrelin is a more powerful stimulator of GH release than either GHRH or GHRP-6. Ageing is associated with a decrease in GH-releasing capacity of ghrelin, whereas this decline is considerably lower for GHRH or GHRP-6.

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Levels of Luteinizing Hormone, Estradiol and Progesterone in Serum During the Estrous Cycle and Pregnancy in the Beagle Bitch

Cited by 114 publications

References 0 publications

Adenohypophyseal function in bitches treated with medroxyprogesterone acetate

Adenohypophyseal function in bitches treated with medroxyprogesterone acetate

Effects of the dopamine agonist cabergoline on the pulsatile and TRH-induced secretion of prolactin, LH, and testosterone in male beagle dogs

Effects of growth hormone secretagogues on the release of adenohypophyseal hormones in young and old healthy dogs

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