Evidence for prolactin as the main luteotrophic factor in the cyclic dog

Okkens, A.C.; Bevers, M.M.; Dieleman, S.J.; Willemse, A.H.

doi:10.1080/01652176.1990.9694266

Cited by 80 publications

(58 citation statements)

References 21 publications

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“…This suggests that not LH but PRL is closely involved in stimulation of the corpus luteum 25 days after ovulation. This result supports the finding that PRL is a luteotrophic factor in dogs [3,19,21,23].…”

Section: Discussionsupporting

confidence: 82%

Influence of a PGF2.ALPHA.-Analogue, Etiproston Tromethamine, on the Functional Corpus Luteum of Dogs

Kirihara

Naganawa

Hori

et al. 2005

The Journal of Veterinary Medical Science

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ABSTRACT. To induce luteal regression-related abortion/delivery and treat pyometra in dogs, various PGF 2α -analogues (PGAs) are administered, but a PGA most appropriate for clinical application in dogs, with a low incidence of side effects, is being investigated. In this study, we compared the effects of etiproston tromethamine (PGA-E), which has not been investigated in dogs, with those of cloprostenol (PGA-C), which is routinely used in dogs. A single dose of PGA-E at 100, 200, 400 or 800 µg or PGA-C at 12.5, 25, 50 or 100 µg was administered to beagles (n=5 per group) 25 days after ovulation, when the corpus luteum was in the functional phase. We compared the state of luteal regression by measuring plasma progesterone levels. As side effects, the incidences of salivation, vomiting, tachypnea, diarrhea and the drop in body temperature were investigated. In the 400-µg and 800-µg groups treated with PGA-E, the mean intervals from administration until luteal regression were 18.6 days and 31.2 days, respectively. In the dogs treated with 50 µg or more of PGA-C, luteal regression was noted 2 days after administration. The above side effects were observed for 3 hr after administration of PGA-E/PGA-C. In the dogs treated with 800 µg of PGA-E, the mean body temperature was 36.7°C 4 hr after administration; hypothermia persisted. PGA-E may be less useful than PGA-C for promoting luteal regression in dogs in clinical application.

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Section: Discussionsupporting

confidence: 82%

Influence of a PGF2.ALPHA.-Analogue, Etiproston Tromethamine, on the Functional Corpus Luteum of Dogs

Kirihara

Naganawa

Hori

et al. 2005

The Journal of Veterinary Medical Science

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“…This concerns mostly the first half of dioestrus, on the one hand, when the canine CL is being formed and passes through its highest steroidogenic and metabolic capacity. On the other hand, for the second half of canine dioestrus (Okkens et al 1990), prolactin appears to be the most important luteotrophic factor.…”

Section: Discussionmentioning

confidence: 99%

Glucose transporter 1 expression accompanies hypoxia sensing in the cyclic canine corpus luteum

et al. 2014

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The canine corpus luteum (CL) functions as a source of progesterone (P 4 ) and 17b-oestradiol (E 2 ); however, the transport of energy substrates to maintain its high hormonal output has not yet been characterised. This study involved the localisation and temporal distribution of the facilitative glucose transporter 1 and the quantification of the corresponding protein (GLUT1) and gene (SLC2A1) expression. Some GLUT1/SLC2A1 regulatory proteins, such as hypoxia-inducible factor 1a (HIF1A) and fibroblast growth factor 2 (FGF2); mRNAs, such as HIF1A, FGF2 and vascular endothelial growth factor A (VEGFA); and VEGFA receptors 1 and 2 (FLT1 and KDR) were also analysed from days 10 to 70 after ovulation. Additionally, plasma P 4 and E 2 levels were assessed via chemiluminescence. Moreover, the canine KDR sequence has been cloned, thereby enabling subsequent semi-quantitative PCR analysis. Our results demonstrate time-dependent variations in the expression profile of SLC2A1 during dioestrus, which were accompanied by highly correlated changes (0.84!r!0.98; P!0.03) in the gene expression of HIF1A, VEGF and FLT1 as well as in P 4 plasma concentrations. FGF2 mRNA correlated with E 2 plasma concentrations (rZ0.61; PZ0.01). Our data reveal that the glucose transporter is regulated throughout the CL lifespan and suggest that CL depends on the sensing of hypoxia and the status of luteal vascularisation. Moreover, time-dependent expression of GLUT1/SLC2A1 may lie underneath increased metabolic and energetic requirements for sustaining P 4 production.

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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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Evidence for prolactin as the main luteotrophic factor in the cyclic dog

Cited by 80 publications

References 21 publications

Influence of a PGF2.ALPHA.-Analogue, Etiproston Tromethamine, on the Functional Corpus Luteum of Dogs

Influence of a PGF2.ALPHA.-Analogue, Etiproston Tromethamine, on the Functional Corpus Luteum of Dogs

Glucose transporter 1 expression accompanies hypoxia sensing in the cyclic canine corpus luteum

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

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