Ketoprofen in horses: Metabolism, pharmacokinetics, and effects on inflammatory biomarkers.

Ketoprofen is an anti-inflammatory drug that is commonly administered to racehorses for the alleviation of musculoskeletal pain and inflammation. This study represents a comprehensive examination of the metabolism (in vivo and in vitro), pharmacokinetics and ex vivo pharmacodynamics, of ketoprofen in horses. The in vitro metabolism as well as specific enzymes responsible for metabolism was determined by incubating liver microsomes and recombinant CYP450 and UGT enzymes with ketoprofen.

Phenylpiperidine opioid effects on isoflurane minimum alveolar concentration in cats.

Different structurally related phenylpiperidine opioids exhibit different isoflurane-sparing effects in cats. Because minimum alveolar concentration (MAC) in cats is affected only by very high plasma concentrations of some phenylpiperidine opioids, we hypothesized these effects are caused by actions on nonopioid receptors. Using a prospective, randomized, crossover design, six cats were anesthetized with isoflurane, intubated, ventilated, and instrumented.

Equine fetal adrenal, gonadal and placental steroidogenesis.

The authors apologize for errors in Figure 6 of their article published in the October 2017 issue of Reproduction (vol 154 iss 4 pp 445–454). The authors explain that the addition of data (Figure 6) on steroid concentrations in the chorioallantois to their manuscript on fetal adrenal and fetal gonadal steroids during development of the equine fetus was made in response to reviewer comments. However, in compiling, summarizing and graphing the data, the wrong units were used in the final figure.

Equine placentitis is associated with a downregulation in myometrial progestin signaling†.

The current study aimed to elucidate the mechanisms underlying myometrial activation during equine placentitis related to progestogens and the progesterone receptor signaling pathways. Placentitis was induced via intracervical inoculation with Streptococcus equi ssp zooepidemicus in mares at approximately 290 days of gestation (placentitis group; n = 6) with uninoculated gestationally matched mares as controls (n = 4). Mares in the placentitis and control groups were euthanized, and myometrial samples were collected from two regions: region 1-parallel to active placentitis lesion with placental separation in placentitis group (P1) or caudal pole of the placenta in control group (C1); and region 2-parallel to apparently normal placenta without separation in placentitis group (P2) or uterine body in control group (C2).

Steroidogenic enzyme activities in the pre- and post-parturient equine placenta.

Steroidogenic enzymes in placentas shape steroid hormone profiles in the maternal circulation of each mammalian species. These include 3β-hydroxysteroid dehydrogenase/Δ5-4 isomerase (3βHSD) and 17α-hydroxylase/17,20-lyase cytochrome P450 (P450c17) crucial for progesterone and androgen synthesis, respectively, as well as aromatase cytochrome P450 (P450arom) that converts Δ4-androgens to estrogens. 5α-reductase is another important enzyme in equine placentas because 5α-dihydroprogesterone (DHP) sustains pregnancy in the absence of progesterone in the second half of equine pregnancy.

A comparison of progesterone assays for determination of peripheral pregnane concentrations in the late pregnant mare.

During the latter half of gestation in mares, there is a complex milieu of pregnanes in peripheral blood. Progesterone concentrations are often assessed by immunoassay during late gestation as a measure of pregnancy well-being; however, interpretation of results is complicated by the numerous cross-reacting pregnanes present in high concentrations during late gestation. Further, many mares are supplemented with an exogenous progestin, altrenogest, which may also cross-react with existing assays and further confound interpretation.

Pharmacokinetics and selected pharmacodynamics of trazodone following intravenous and oral administration to horses undergoing fitness training.

OBJECTIVE To measure concentrations of trazodone and its major metabolite in plasma and urine after administration to healthy horses and concurrently assess selected physiologic and behavioral effects of the drug. ANIMALS 11 Thoroughbred horses enrolled in a fitness training program. PROCEDURES In a pilot investigation, 4 horses received trazodone IV (n = 2) or orally (2) to select a dose for the full study; 1 horse received a vehicle control treatment IV.

Equine fetal adrenal, gonadal and placental steroidogenesis.

Equine fetuses have substantial circulating pregnenolone concentrations and thus have been postulated to provide significant substrate for placental 5α-reduced pregnane production, but the fetal site of pregnenolone synthesis remains unclear. The current studies investigated steroid concentrations in blood, adrenal glands, gonads and placenta from fetuses (4, 6, 9 and 10 months of gestational age (GA)), as well as tissue steroidogenic enzyme transcript levels. Pregnenolone and dehydroepiandrosterone (DHEA) were the most abundant steroids in fetal blood, pregnenolone was consistently higher but decreased progressively with GA.

Pharmacokinetics and pharmacodynamics of meldonium in exercised thoroughbred horses.

Although developed as a therapeutic medication, meldonium has found widespread use in human sports and was recently added to the World Anti-Doping Agency's list of prohibited substances. Its reported abuse potential in human sports has led to concern by regulatory authorities about the possible misuse of meldonium in equine athletics. The potential abuse in equine athletes along with the limited data available regarding the pharmacokinetics and pharmacodynamics of meldonium in horses necessitates further study.

Compounding of Veterinary Drugs for Equine Practitioners.

Equine practitioners should follow these recommendations when using compounded medications: (1) the decision must be veterinary driven, based on a valid veterinarian-client-patient relationship and on evidence-based medicine; (2) compliance with the Animal Medicinal Drug Use Clarification Act of 1994; and (3) use limited to (a) horses for which no other method or route of drug delivery is practical; (b) those drugs for which safety, efficacy, and stability have been demonstrated; or (c) disease conditions for which a quantifiable response to therapy or drug concentration can be monitored.

Pharmacokinetics of betamethasone in plasma, urine, and synovial fluid following intra-articular administration to exercised thoroughbred horses.

The use of corticosteroids, such as betamethasone, in performance horses is tightly regulated. The objective of the current study was to describe the plasma pharmacokinetics of betamethasone as well as time-related urine and synovial fluid concentrations following intra-articular administration to horses. Twelve racing-fit adult Thoroughbred horses received a single intra-articular administration (9 mg) of a betamethasone sodium phosphate and betamethasone acetate injectable suspension into the right antebrachiocarpal joint.

Pharmacokinetic and pharmacodynamics of xylazine administered to exercised thoroughbred horses.

There is limited data describing xylazine serum concentrations in the horse and no reports of concentrations beyond 24 hours. The primary goal of the study reported here was to update the pharmacokinetics of xylazine following intravenous (IV) administration in order to assess the applicability of current regulatory recommendations. Pharmacodynamic parameters were determined using PK-PD modeling.

Pharmacokinetics of a combination of amikacin sulfate and penicillin G sodium for intravenous regional limb perfusion in adult horses.

The aim of this study was to determine the pharmacokinetics of amikacin and penicillin G sodium when administered in combination as an intravenous regional limb perfusion (IVRLP) to horses. Seven healthy adult horses underwent an IVRLP in the cephalic vein with 2 g of amikacin sulfate and 10 mill IU of penicillin G sodium diluted to 60 mL in 0.9% saline.

The dynamic steroid landscape of equine pregnancy mapped by mass spectrometry.

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) allowed comprehensive analysis of various steroids detectable in plasma throughout equine gestation. Mares (n=9) were bled serially until they foaled. Certain steroids dominated the profile at different stages of gestation, clearly defining key physiological and developmental transitions.

Pregnancy without progesterone in horses defines a second endogenous biopotent progesterone receptor agonist, 5α-dihydroprogesterone.

One of the most widely accepted axioms of mammalian reproductive biology is that pregnancy requires the (sole) support of progesterone, acting in large measure through nuclear progesterone receptors (PRs) in uterine and cervical tissues, without which pregnancy cannot be established or maintained. However, mares lack detectable progesterone in the latter half of pregnancy. Instead of progesterone, several (mainly 5α-reduced) pregnanes are elevated and have long been speculated to provide progestational support in lieu of progesterone itself.

Resveratrol potentiates effects of simvastatin on inhibition of rat ovarian theca-interstitial cells steroidogenesis.

Background: Polycystic ovary syndrome (PCOS) is characterized by ovarian enlargement, hyperplastic theca compartment and increased androgen production due to, at least in part, excessive expression of several key genes involved in steroidogenesis. Previously, our group has demonstrated that simvastatin, competitive inhibitor of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA reductase), a rate-limiting step of the mevalonate pathway, reduces rat-theca interstitial cell steroidogenesis by inhibiting Cyp17a1 gene expression, the key enzyme of the androgen biosynthesis pathway. Recently, we demonstrated that resveratrol, a bioflavonoid abundant in red grapes, decreases rat theca-interstitial cell steroidogenesis and this suppressive effect is mediated through mechanisms independent of the mevalonate pathway.

Comparison of effects of different statins on growth and steroidogenesis of rat ovarian theca-interstitial cells.

Statins are competitive inhibitors of 3-hydroxy-3-methyl-glutaryl-CoA reductase, the rate-limiting enzyme of the cellular production of cholesterol and other products of the mevalonate pathway. Statins exert hepatic and extrahepatic effects, modulating the function of various tissues and organs, including ovaries. Previously, we have demonstrated that simvastatin inhibited cellular proliferation and reduced androgen production by ovarian theca-interstitial cells.

Effects of three antagonists on selected pharmacodynamic effects of sublingually administered detomidine in the horse.

Objective: To describe the effects of alpha2 -adrenergic receptor antagonists on the pharmacodynamics of sublingual (SL) detomidine in the horse.

Study Design: Randomized crossover design.

Animals: Nine healthy adult horses with an average age of 7.

Population pharmacokinetics of doxycycline in the tears and plasma of northern elephant seals (Mirounga angustirostris) following oral drug administration.

Objective: To assess tear and plasma concentrations of doxycycline following oral administration to northern elephant seals (Mirounga angustirostris).

Design: Pharmacokinetic study.

Animals: 18 juvenile northern elephant seals without signs of ocular disease.

In vivo and in vitro evaluation of the effects of domperidone on the gastrointestinal tract of healthy horses.

Objective: To determine the effects of domperidone on in vivo and in vitro measures of gastrointestinal tract motility and contractility in healthy horses.

Sample: 18 adult horses and tissue samples from an additional 26 adult horses.

Procedures: Domperidone or placebo paste was administered to healthy horses in a 2-period crossover study.

In vivo and in vitro effects of neostigmine on gastrointestinal tract motility of horses.

Objective: To determine the response to neostigmine of the contractile activity of the jejunum and pelvic flexure and the effects of a continuous rate infusion (CRI) of neostigmine in horses.

Animals: 7 adult horses and tissue from 12 adult horses.

Procedures: A CRI of neostigmine (0.

Pharmacokinetics, pharmacodynamics, and safety of zoledronic acid in horses.

Objective: To determine the pharmacokinetics, pharmacodynamics, and safety of zoledronic acid in horses.

Animals: 8 healthy horses.

Procedures: A single dose of zoledronic acid (0.

Letrozole increases ovarian growth and Cyp17a1 gene expression in the rat ovary.

Objective: To evaluate the effects of letrozole on ovarian size and steroidogenesis in vivo, as well as on proliferation and steroidogenesis of theca-interstitial cells alone and in coculture with granulosa cells using an in vitro model.

Design: In vivo and in vitro studies.

Setting: Research laboratory.

Evaluation of squeeze-induced somnolence in neonatal foals.

Objective: To test the hypothesis that application of a rope restraint device would result in behavioral, electroencephalographic, and humoral changes consistent with sleep and analgesia in neonatal foals.

Animals: 8 healthy neonatal foals.

Procedures: Following acclimatization to experimental conditions, each foal underwent a series of assessments before and during or at the end of a period of restraint via application of a restraint device (soft linen rope).