Bromocriptine-induced premature oestrus is associated with changes in the pulsatile secretion pattern of follicle-stimulating hormone in beagle bitches

Kooistra, H.S.; Okkens, A.C.; Bevers, M.M.; Popp-Snijders, C.; Haaften, B. van; Dieleman, S.J.; Schoemaker, J.

doi:10.1530/jrf.0.1170387

Cited by 22 publications

(26 citation statements)

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“…The high GnRH secretion associated with MPA treatment postulated in the previous paragraph may therefore have resulted in desensitization of the response of the gonadotropes to GnRH. The decline to pretreatment FSH levels and the decrease in responsiveness of pituitary FSH secretion to GnRH are probably part of the estrus-preventing effects of MPA, because increased FSH secretion is a critical event in the initiation of ovarian folliculogenesis [46,47]. In other words, MPA treatment for estrus prevention may prohibit the normal rise in plasma FSH concentration during late anestrus.…”

Section: Discussionmentioning

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: Discussionmentioning

confidence: 99%

Adenohypophyseal function in bitches treated with medroxyprogesterone acetate

Beijerink

Bhatti

Okkens

et al. 2007

Domestic Animal Endocrinology

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“…The decline in prolactin concentration is not the key event triggering anoestrus termination. This appears to be a consequence of other central dopaminergic effects shown by cabergoline but not by other antiprolactin drugs, like metergoline, acting as secotonin antagonists (Kooistra et al. 1999a).…”

Section: Discussionmentioning

confidence: 99%

“…The administration of some dopamine agonists, like bromocriptine or cabergoline, is associated with an increase in basal plasma FSH concentration, resulting in the shortening of the interoestrus interval (Okkens et al. 1997; Kooistra et al. 1999a).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Cabergoline and Buserelin Efficacy for Oestrous Induction in the Bitch

Rota¹,

Mollo²,

Marinelli

et al. 2003

Reprod Domestic Animals

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The purpose of this work was to compare two different protocols of oestrous induction, using either a dopamine agonist (cabergoline) or a GnRH agonist (buserelin) in anoestrus bitches. The clinical trial involved 22 Beagle bitches, randomly allotted to two treatment groups: group A (n = 12) was orally administered cabergoline (Galastop(R); Centralvet-Vetem, Milan, Italy; 5 microg/kg SID), until the onset of cytological oestrus or for a maximum of 30 days and group B (n = 10) was treated with buserelin acetate, (Suprefact(R); Aventis Pharma, Milan, Italy), administered subcutaneously t.i.d., at 1.5 microg/kg for 11 days and 0.75 microg/kg for the following 3 days. Blood samples were collected twice a week to measure progesterone and prolactin concentration. Both cabergoline and buserelin produced a significant early decline in prolactin concentration (p < 0.01), but the effect of cabergoline lasted longer. Progesterone concentration was significantly affected by buserelin administration, showing a significant increase (p < 0.01) from day 3 to day 6 of treatment. Cabergoline confirmed its effectiveness in inducing oestrus as 10 of 12 bitches responded to the treatment, were mated and whelped. On the contrary, oestrus was observed in only three of 10 buserelin-treated bitches and in two of them 7 and 13 days after the end of treatment. These same two bitches accepted mating and conceived. The results suggest that in a clinical setting, dopaminergic treatment is the treatment of choice as it yields more consistent results and involves a much easier administration protocol.

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“…61 In healthy young men manipulating hormonal levels to decrease prolactin with cabergoline increases sexual desire and arousal in laboratory conditions. 62 It has been reported that [63][64][65] cabergoline could reduce the length of anestrous and induce a fertile estrous period in bitches. Improved penile erections and libido caused by dopaminergic compounds occaSalvage of sildenafil failures with cabergoline MR Safarinejad sionally can be perceived as adverse events.…”

Section: Discussionmentioning

confidence: 99%

“…For question 4, the mean score was 3.7 (51.4% increase from baseline mean score of 1.8) for the cabergoline group compared with 2 (20% increase from baseline mean score of 1.6) for the placebo group. At the 6-month end point, 64 Salvage of sildenafil failures with cabergoline MR Safarinejad at sexual intercourse in the cabergoline group as compared with 6% successful attempts during placebo treatment (P ¼ 0.02). Data from patients' event logs showed no evidence of a treatment period effect.…”

Section: Efficacymentioning

confidence: 99%

Salvage of sildenafil failures with cabergoline: a randomized, double-blind, placebo-controlled study

Safarinejad¹

2006

Int J Impot Res

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To evaluate the safety and efficacy of cabergoline in men with erectile dysfunction (ED) who did not respond to sildenafil. Four hundred two sildenafil nonresponders aged from 21 to 59 years were included in the study. Patients were randomly divided into group 1, those who received 0.5-1 mg cabergoline weekly for 6 months and group 2, who received placebo for the same period. They underwent preliminary assessment, including medical and sexual history, self-administered International Index of Erectile Function (IIEF) and intravaginal ejaculatory latency time (IVELT) evaluation. Standard biochemistry and hematological laboratory tests, and measurement of serum testosterone and prolactin levels were also carried out. When indicated, other tests were used to establish the diagnosis of vasculogenic and neurogenic ED, including penile color duplex Doppler ultrasonography, pudendal nerve conduction test and impaired sensory-evoked potentials studies. The efficacy of two treatments was assessed every 2 weeks during treatment, at the end of the study, using responses to IIEF, IVELT evaluation, mean intercourse satisfaction domain, mean weekly coitus episodes and adverse drug effects. The trial was completed by 370 (92%) men. Positive clinical results were seen in 31.2% of patients in the cabergoline group compared with 7.1% of patients in the placebo group (P ¼ 0.04). The mean weekly intercourse episodes increased from pretreatment values of 1.4 and 1.2 to 2.2 and 1.4, for cabergoline and placebo, respectively (P ¼ 0.04). Baseline mean intercourse satisfaction domain values of IIEF 10 and 11 reached to 15 and 10 at 6-month treatment in groups 1 and 2, respectively (P ¼ 0.04). The IVELT after cabergoline and placebo gradually increased from 98 and 101 s to approximately 242 and 116 s, respectively (P ¼ 0.001). More drug-related adverse effects occurred in cabergoline group and 12 (5.9%) had to discontinue treatment (P ¼ 0.001). Cabergoline is moderately effective salvage therapy for sildenafil nonresponse. Further studies with different dosages and treatment regimens are necessary to draw final conclusions on the efficacy of this drug in ED.

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Bromocriptine-induced premature oestrus is associated with changes in the pulsatile secretion pattern of follicle-stimulating hormone in beagle bitches

Cited by 22 publications

References 0 publications

Adenohypophyseal function in bitches treated with medroxyprogesterone acetate

Adenohypophyseal function in bitches treated with medroxyprogesterone acetate

Evaluation of Cabergoline and Buserelin Efficacy for Oestrous Induction in the Bitch

Salvage of sildenafil failures with cabergoline: a randomized, double-blind, placebo-controlled study

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