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T D Braden

Publications and source records attributed to T D Braden.

At least 19 recordsLinked to original sources
PubMed2001

Expression of insulin-like growth factor binding protein (IGFBP)-3, and the effects of IGFBP-2 and -3 in the bovine corpus luteum.

The present study was conducted to gain insight into the insulin-like growth factor (IGF) system in the bovine corpus luteum (CL). Specific aims were to measure the levels of IGF binding protein-3 (IGFBP-3) and RNA encoding IGFBP-3 in the CL throughout diestrus, and to investigate the effects of IGFBP-2 and -3 on IGF-I-stimulated progesterone (P4) production and IGF-I-receptor binding. Bovine CL were collected from a local abattoir and classified according to stage of diestrus based on anatomical characteristics. Corpora lutea from early, mid and late diestrus were each analyzed for the presence of IGFBP-3 by ligand blot analysis, and for RNA encoding IGFBP-3 by Northern blot analysis. Dissociated cells from mid-cycle CL were treated with IGF-I, IGFBP-2 or -3, or a combination of IGF-I and IGFBP-2 or -3. The effect of IGFBP-2 and IGFBP-3 on [(125)I] IGF-I binding to its receptor on CL plasma membranes also was investigated. IGFBP-3 protein and RNA expression were higher in early CL, compared to mid or late CL (p < 0.05). IGF-I stimulated P4 production in a dose-dependant manner (p < 0.05). IGFBP-2 and -3 blocked the stimulatory effect of IGF-I on P4 production (p < 0.05). Both IGFBP-2 and -3 inhibited [(125)I]-IGF-I binding to its receptor in a dose-dependant manner. These results demonstrate that IGFBP-3 protein and RNA are expressed predominantly during early diestrus in the bovine CL. Moreover, both IGFBP-2 and -3 can modulate IGF-I actions in the CL by interfering with binding of IGF-I to its receptor.

Animals↗
PubMed2001

Diethylstilbestrol-treated adult rats with altered epididymal sperm numbers and sperm motility parameters, but without alterations in sperm production and sperm morphology.

In this study, we characterized estrogenic effects of diethylstilbestrol (DES) on reproductive parameters in male rats to identify a minimal dose level that alters epididymal and sperm functions but has little or no effect on sperm production and/or spermatogenesis. Adult rats (five animals/group) received s.c. injections of 0.2 ml of corn oil containing DES at a rate of 1.0 mg, 200 microg, 40 microg, 8 microg, 1.6 microg, or 320 ng x rat(-1) x day(-1) for 12 days. The control group received corn oil only. DES effects were similar in the 8-microg group and higher dose groups and included significant (P < or = 0.05) reductions in 1) absolute and relative weights of the head and body of the epididymis (EP), tail of the EP, and seminal vesicle, 2) numbers of sperm in both regions of the EP, and 3) motility characteristics in sperm collected from the tail of the EP. Conversely, no significant changes were observed in relative testis weight, daily sperm production, spermatogenesis, seminiferous epithelial height in stage VII, and sperm morphology. All of the above parameters in the 1.6-microg group (except seminal vesicle weight) and 320-ng group were comparable to those of controls. Plasma testosterone (T) level was reduced to an almost undetectable level in the > or = 8-microg groups and to a very low level in the 1.6-microg group (0.35 vs. 2.36 ng/ml in controls or 320-ng group), but LH level was unaltered. In a parallel fertility study, males received DES at a rate of 40, 8, or 1.6 microg x rat(-1) x day(-1) for 12 days prior to and 12 days during cohabitation (1:1) with untreated females. Of the 15 females cohabited with treated males (5 females/dose), none in the 40-microg and 8-microg groups and 1 in the 1.6-microg group formed a copulatory plug and delivered 8 pups, in contrast to 5/5 copulatory plugs and 13-15 pups/litter in the controls. DES at a rate of 8 microg x rat(-1) x day(-1) for 12 days reduced EP weights, sperm numbers in the EP, and sperm motility patterns but caused minimal to no alterations in daily sperm production, spermatogenesis, or sperm morphology. Factors other than T, or in addition to lower T, may be responsible for DES-induced reproductive disorders (despite lower T, sperm contents and sperm motility patterns in the EP were normal in the 1.6-microg group). Deficits in EP sperm functions and/or sexual behavior (as evident from absence of copulatory plugs) probably accounted for reduced fertility in treated males.

Animals↗
PubMed2001

Luteal and clinical response following administration of dinoprost tromethamine or cloprostenol at standard intramuscular sites or at the lumbosacral acupuncture point in mares.

OBJECTIVE: To determine whether administration of a microdose of prostaglandin at the BAI HUI acupuncture point offers any advantage over IM injections for luteolysis, ovulatory interval, or systemic response in mares. ANIMALS: 17 mature cycling mares, 3 to 20 years of age and weighing 400 to 500 kg. PROCEDURE: Conventional and microdoses of the prostaglandin dinoprost tromethamine (PGF2alpha), the analogue cloprostenol, or sterile water (control) were administered to mares in 7 treatment groups. Treatments were assigned by dose, administration site (semimembranosus, semitendinosus, or lumbosacral region), and treatment type (PGF2alpha, analogue, or sterile water). Mares were observed for ovulatory interval and systemic response to treatment, including heart, and respiratory rates, rectal temperature, and sweat score. Plasma progesterone concentrations were also determined at the time of treatment and at 24-hour intervals for 96 hours following treatment. RESULTS: Ovulatory interval was shortened and progesterone concentrations decreased in prostaglandin-treated mares, compared with control mares, regardless of dose or treatment site. However, no differences in ovulatory interval were observed among prostaglandin-treated mares. Mares treated with conventional doses of PGF2alpha had greater systemic responses than mares treated with microdoses of PGF2alpha or sterile water. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of prostaglandins at the BAI HUI acupuncture point does not appear to offer any advantage over administration at standard IM injection sites for induction of luteolysis or to shorten the ovulatory interval. However, administration of a microdose of the analogue cloprostenol was effective at inducing luteolysis and shortening ovulatory interval regardless of administration site.

Abortifacient Agents, Nonsteroidal↗
PubMed1999

Radiographic, biomechanical, and pathologic effects of hemoglobin glutamer-200 in dogs undergoing cemented total hip arthroplasty.

OBJECTIVE: To determine whether use of hemoglobin glutamer-200 (bovine) as a partial blood volume replacement in dogs undergoing cemented total hip replacement caused any deleterious effects on the bone-cement or cement-prosthesis interface, exerted any deleterious effects on body organs, or caused any complications during the anesthetic, immediate recovery, or long-term recovery period. ANIMALS: 9 adult dogs. METHODS: Dogs were anesthetized, and 15% of the blood volume was removed. Simultaneously, lactated Ringer's solution was infused, and 6 dogs were given hemoglobin glutamer (1 g/kg of body weight, IV). Unilateral total hip replacement was performed. Limb use was assessed visually, and force-plate and radiographic evaluations were performed before, and 8 weeks after, surgery. Eight weeks after surgery, dogs were euthanatized, necropsies were performed, and prosthetic component pullout forces were determined. RESULTS: There were no significant differences between treated and control dogs in regard to biomechanical (visual assessment of gait, force-plate analysis, femoral and acetabular component pullout forces) and pathologic evaluations (physical examination, CBC, serum biochemical analyses, necropsy, and histologic evaluations). Radiographic signs of loosening of the femoral component were seen in 4 dogs treated with hemoglobin glutamer. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of hemoglobin glutamer as a blood substitute did not appear to have any deleterious effects in dogs undergoing total hip arthroplasty. The radiographic findings, which were discordant with the biomechanical results, merit further investigation.

Acetabulum↗
PubMed1998

Keratinocyte growth factor expression by the bovine corpus luteum.

Communication between cells of the corpus luteum (CL) is thought to be necessary for normal luteal function. Keratinocyte growth factor (KGF) is produced by mesenchymally derived cells in numerous tissues and acts on epithelial cells. In bovine follicles, theca cells produce KGF, which can stimulate granulosa cell proliferation. Whether KGF is produced by ovarian cells after luteinization is unknown. Our objective was to determine whether KGF mRNA and protein were present in bovine luteal tissue, and if so, to determine what type(s) of luteal cells contains KGF. CL (n = 3-4/day) were obtained from specific days throughout diestrus. Presence of KGF mRNA in CL was determined using a porcine KGF anti-sense cRNA probe. Northern analyses of luteal tissue poly(A)+ RNA revealed a single transcript (approximately 2.0 kilobases), the quantity of which did not change throughout diestrus. Western analysis revealed an immunoreactive band (28 kDa) in luteal tissues and theca cell homogenates that was absent from granulosa cell homogenates. Immunocytochemistry showed KGF predominantly in theca and small luteal cells. Results indicate that bovine CL produce and contain KGF, which is primarily localized in small luteal cells. Therefore, KGF may participate in paracrine communication within the bovine CL.

Animals↗
PubMed1998

Effects of interleukins on secretion of luteinizing hormone from ovine pituitary cells.

OBJECTIVE: To determine whether cytokines of homologous species might mediate the stimulatory effects of endotoxin on release of luteinizing hormone (LH) from pituitary cells. SAMPLE POPULATION: Cells from pituitary glands collected from 8- to 14-month-old wethers. PROCEDURE: Cells from the anterior pituitary gland were cultured in the presence of recombinant ovine or bovine cytokines (interleukin [IL]-1alpha, IL-1beta, and IL-2), tumor necrosis factor-alpha (TNF), and interferon-gamma (IFN-gamma). Luteinizing hormone that was released into the medium was measured. Cells were also cultured with modulators of signal transduction pathways to evaluate the second messenger system used by IL-1 alpha and IL-1beta. RESULTS: Similar to effects of endotoxin, IL-1alpha and IL-1beta stimulated release of LH. Interleukin 2, TNF, and IFN-gamma did not have a detectable effect on release of LH. Stimulation of LH release by IL-1alpha and IL-1beta required activation of voltage-dependent Ca2+ channels and appeared to involve protein kinase C. CONCLUSIONS: IL-1alpha and IL-1beta may mediate the direct stimulatory effect of endotoxin on release of LH in vitro. Interleukin 2, TNF, and IFN-gamma do not have a direct effect on release of LH; therefore, they do not mediate this effect of endotoxin. CLINICAL RELEVANCE: Stressors, including infection, are often associated with reduced fertility. Infection resulting in endotoxin release, production of interleukins, or both, can lead to direct stimulation of LH release from the pituitary gland. Inopportune release of LH via cytokines may interfere with normal pulsatile release of LH, thereby suppressing gonadal function.

Animals↗
PubMed1997

Effect of gonadotropin-releasing hormone (GnRH) pulse frequency on serum and pituitary concentrations of luteinizing hormone and follicle-stimulating hormone, GnRH receptors, and messenger ribonucleic acid for gonadotropin subunits in cows.

Thirty-two nutritionally anestrous cows were used to determine the effect of the frequency of exogenous GnRH pulses on ovarian follicular growth, serum concentrations of LH and FSH, and concentrations of LH, FSH, GnRH receptors (GnRH-R), messenger RNA (mRNA) for GnRH-R, and mRNA for gonadotropin subunits in the pituitary. Cows were randomly assigned to one of four treatments: 2 micrograms GnRH infused (i.v.) continuously during 1 h, 2 micrograms GnRH infused during 5 min once every hour, 2 micrograms GnRH infused during 5 min once every fourth hour, or saline (control) for 13 days. Infusion of GnRH every hour increased LH concentrations in serum (P < 0.05), but FSH concentrations were not affected by GnRH infusion. Luteal activity (LA) was assessed by the presence of corpora lutea and/or serum progesterone greater than 1 ng/ml. Six of eight cows infused with GnRH every hour had LA by day 13, whereas only 25% of cows infused either continuously or with a pulse every fourth hour had LA by day 13. None of the control cows had LA during the experiment (P < 0.01). Concentrations of LH and FSH in the pituitary were significantly reduced when GnRH was infused hourly or continuously. Concentrations of common alpha and FSH beta mRNA were not influenced by treatment. However, continuous infusion of GnRH decreased (P < 0.05) LH beta mRNA subunit. Concentrations of GnRH-R (P < 0.1) and GnRH-R mRNA (P < 0.05) were reduced when GnRH was infused continuously. We concluded that pulsatile secretion of LH is necessary for follicular growth and LA in beef cattle, and GnRH treatment differentially regulates LH and FSH gene transcription and serum concentrations of LH and FSH in cattle.

Animals↗
PubMed1996

Use of force-plate analysis of gait to compare two surgical techniques for treatment of cranial cruciate ligament rupture in dogs.

OBJECTIVE: To use ground reaction forces and related impulses as an objective measurement of limb function in the comparison of 1 extracapsular and 1 intracapsular surgical technique for repair of cranial cruciate ligament rupture in dogs. ANIMALS: 18 healthy dogs. DESIGN: All dogs underwent force-plate analysis of gait prior to transection of the left cranial cruciate ligament. The dogs were randomly allotted to 3 groups. The ligamentous instability was corrected, using a modified retinacular imbrication technique (MRIT) in 1 group and an under-and-over technique in another group. No attempt was made to correct the ligamentous instability in a control group. Clinical grading of lameness and force-plate analysis of gait were performed at 4, 8, 12, 16, and 20 weeks after surgery. PROCEDURE: Peak vertical force and vertical, braking, and propulsion impulses were recorded for each limb at each time. The degree of clinical lameness was graded at each time. RESULTS: Left hind limb peak vertical forces and vertical impulses were significantly decreased at all times after surgery in the control and under-and-over technique group, compared with values before surgery. Dogs of the MRIT group had improved by 20 weeks, with no significant differences between left hind limb peak vertical forces or vertical impulses recorded before surgery and at 20 weeks. CONCLUSION: Peak vertical forces and vertical impulses in dogs undergoing MRIT repair after experimentally created cranial cruciate ligament rupture are not significantly different when values recorded for the operated limb at 20 weeks after surgery are compared with those recorded prior to surgery.

Analysis of Variance↗
PubMed1993

Effects of subject velocity on force plate-measured ground reaction forces in healthy greyhounds at the trot.

Force plate gait analysis was used to study the effects of subject velocity on ground reaction forces. Seven adult Greyhounds were trotted at 3 distinct velocities: 1.5 to 1.8 m/s, 2.1 to 2.4 m/s, and 2.7 to 3.0 m/s. Forelimb and hind limb peak vertical forces increased with increase in velocity (P < 0.05). Forelimb and hind limb vertical impulses decreased as velocity increased (P < 0.05). Significant variations were not observed for craniocaudal or mediolateral peak forces or impulses. It was concluded that velocity significantly (P < 0.05) influenced ground reaction forces and impulses, and must be controlled in experimental design.

Analysis of Variance↗
PubMed1992

Three-plane intertrochanteric osteotomy for treatment of early stage hip dysplasia.

Indications, preoperative planning, and surgical procedure for the three-plane intertrochanteric osteotomy are described. The goal of this procedure is to decrease the biomechanical stress in the coxofemoral joint, thereby relieving pain associated with early stage canine hip dysplasia. Clinical signs of pain are alleviated for many years.

Animals↗
PubMed1992

Activin-A stimulates the synthesis of gonadotropin-releasing hormone receptors.

The number of GnRH receptors on gonadotropes is regulated by GnRH as well as by heterologous modulators. We have used the density shift technique to measure the synthetic rate of GnRH receptors in pituitary cell cultures and found it to be stimulated by GnRH, an action that is antagonized by inhibin. In the present study, we evaluated the effects of activin-A on the GnRH receptor synthesis rate as well as effects of activin on stimulation of GnRH receptor synthesis by the homologous hormone. Recombinant human activin-A (50 ng/ml) was incubated with pituitary cell cultures from female weanling rats and the incorporation of densely labeled amino acids into receptors for GnRH was measured. The rate of GnRH receptor synthesis of cells treated with activin (50 ng/ml) together with either GnRH (0.1 ng/ml) or inhibin (12 ng/ml) was also quantified. Activin significantly stimulated the synthetic rate of GnRH receptors similarly to that observed after GnRH treatment (time for synthesis of half the population of GnRH receptors was 12.6 +/- 1.1, 16.1 +/- 1.3 vs. 28.3 +/- 1.2 h for GnRH, activin, and control, respectively), although the time course for stimulation by GnRH and activin appeared to differ. Inclusion of activin in cultures did not affect homologous stimulation of GnRH receptor synthesis. The stimulatory effects of activin were unaffected by combined treatment with inhibin (t1/2 of synthesis 17.2 +/- 2.0 h). Together, these data indicate that activin stimulates GnRH receptor synthesis in cell culture through a distinct mechanism from GnRH. Additionally, inhibin did not antagonize the stimulatory effects of activin on synthesis of GnRH receptors. This is, to our knowledge, the first demonstration of an action of activin-A on GnRH receptor synthesis.

Activins↗
PubMed1992

SIIp: a unique secretogranin/chromogranin of the pituitary released in response to gonadotropin-releasing hormone.

A monoclonal antibody prepared by immunization of mice with a rat pituitary granule fraction stained a single band on a Western blot of pituitary homogenate (bovine, ovine, porcine, or rat) with an apparent mol wt of 78,000 (7.5% acrylamide gel in sodium dodecyl sulfate) and pI 5.0-5.1 (isoelectric focusing). Subcellular fractionation studies of rat pituitaries indicated that the determinant of the monoclonal antibody was markedly enriched in the secretory granule fraction, an observation that was independently confirmed by immunohistochemistry of intact cells. Immunohistochemistry also indicated that this determinant was selectively located in gonadotropes and thyrotropes. On Western blots, this band comigrated with adrenal secretogranin-II (SII; chromogranin-C), had the same N-terminal sequence (six amino acids), and was heat stable (95 C; 10 min). The pituitary protein containing the determinant for the monoclonal antibody could be precipitated by a polyclonal antibody prepared by immunization of rabbits with the C-terminal sequence of adrenal SII (triodecapeptide). Conversely, the monoclonal antibody precipitated the protein containing the determinant for the polyclonal antibody. While both the monoclonal and polyclonal antisera recognized the pituitary molecule, only the polyclonal antibody recognized SII from the adrenal. A RIA was established and used to assess the release pattern of this molecule from pituitary cell cultures. Release was stimulated by GnRH and blocked by a GnRH antagonist. Release was Ca2+ dependent and stimulated by either phorbol myristyl acetate (a protein kinase-C activator) or NaF (a G-protein activator). GHRH and TRH were not as effective secretogogues as GnRH. The observations that a unique form of SII is present in the pituitary gonadotrope and secreted in response to a specific endocrine stimulus present the possibility that this substance has an endocrine function. Further, the tissue specificity of the determinant suggest that it may be useful for the specific diagnosis and monitoring of pituitary tumors.

Amino Acid Sequence↗
PubMed1991

Posttraumatic osteomyelitis.

Posttraumatic osteomyelitis is the most common type of osteomyelitis in the dog and cat. Poor surgical technique is the leading cause of this disease. Its pathogenesis involves the interaction of an infected wound, avascular bone, and favorable milieu. Treatment usually involves surgery; the goal is to improve the environment. Because treatment is not totally successful and is lengthy and costly, the main emphasis in dealing with this disease should revolve around its prevention.

Animals↗
PubMed1991

The 1990 James A. F. Stevenson Memorial Lecture. Gonadotropin-releasing hormone and its actions.

Gonadotropin-releasing hormone (GnRH) stimulates the release and biosynthesis of gonadotropins, luteinizing hormone, and follicle-stimulating hormone from the pituitary gland. Additionally, GnRH regulates the number of its own receptors on pituitary gonadotropes causing both up- and down-regulation of receptors as well as biosynthesis of GnRH receptors. After exposure to GnRH, gonadotropes become desensitized to further stimulation by GnRH. The mechanisms through which these actions of GnRH are mediated appear to differ. Effects dependent upon extracellular calcium include gonadotropin biosynthesis and release as well as up-regulation of GnRH receptors. Additional actions of GnRH, such as down-regulation of receptors, biosynthesis of receptors, and desensitization, appear to be independent of extracellular calcium. Subsequent studies have ascribed roles for calmodulin and protein kinase C in mediating specific effects of GnRH.

Amino Acid Sequence↗
PubMed1991

Protein kinase-C activation stimulates synthesis of gonadotropin-releasing hormone (GnRH) receptors, but does not mediate GnRH-stimulated receptor synthesis.

Gonadotropes respond to GnRH with LH synthesis and release, desensitization, changes in GnRH receptor number, and GnRH receptor synthesis. Activation of protein kinase-C (PKC) appears to be involved in LH beta gene expression, but is not required for acute LH release, desensitization, or receptor down-regulation. The present studies were conducted to determine whether PKC mediates GnRH-stimulated receptor synthesis. We have adapted the density shift technique to measure the synthesis of GnRH receptors in pituitary culture. Pituitary cells from female weanling rats were exposed to medium containing treatments, dense amino acids (greater than 95% 13C, 15N, and 2H), dialyzed horse serum (10%, vol/vol), and fetal calf serum (2.5%, vol/vol). Treatments consisted of medium alone, phorbol myristate acetate (PMA), phorbol dibutyrate (PdBu), or GnRH. To deplete cells of PKC, cultures were exposed for 8-16 h to 1 microM PMA. Short term treatment with PKC activators (PMA or PdBu, 1 microM) or GnRH (0.1 nM) was given for 30 min. After treatment, GnRH receptors were covalently linked to [125I]Tyr5-azidobenzoyl-D-Lys6-GnRH and solubilized. Newly synthesized (densely labeled) GnRH receptors were separated from normal receptors by velocity sedimentation (156,000 X g; 24 h; 0-20% sucrose) and quantified by gamma-spectroscopy. Treatment with GnRH significantly stimulated the synthesis of GnRH receptors. Treatment of pituitary cell cultures with PMA (8-16 h) also stimulated the synthesis of GnRH receptors, although to a lesser extent than that observed after GnRH treatment. The synthesis of GnRH receptors in response to 0.1 nM GnRH was not different in cells with a normal complement of PKC compared to those depleted of PKC activity. This indicates that the ability of GnRH to stimulate the synthesis of its own receptor is not mediated by PKC. Short term treatment of cell cultures with 1 microM PMA or PdBu (30 min) stimulated GnRH receptor synthesis similar to treatment with 0.1 nM GnRH. When PMA and GnRH were administered simultaneously, GnRH receptor synthesis was stimulated to a greater extent than with either agent alone, suggesting differing mechanisms of action. These results indicate that although activators of PKC can stimulate the synthesis of GnRH receptors, PKC does not mediate the effects of GnRH on homologous receptor synthesis.

Amino Acids↗
PubMed1990

Clinical evaluation of intertrochanteric osteotomy for treatment of dogs with early-stage hip dysplasia: 37 cases (1980-1987).

Between May 1980 and May 1987, intertrochanteric osteotomy was performed on 43 hips of 37 dogs (6 bilateral procedures) with early-stage hip dysplasia, with the objectives of improving hip biomechanics and reducing discomfort. Clinical evaluation consisted of: questionnaire, and/or orthopedic examination, and/or report from owner(s) via telephone. At least 1 form of evaluation was conducted for 42 of 43 hips (98%). On the basis of orthopedic examination findings, 27 of 33 hips (84%) were functionally good or normal at postoperative month 15 (on average). On the basis of owner report, 19 of 28 hips (68%) were functionally good or normal at postoperative month 11 (on average). On the basis of questionnaire data, 17 of 24 hips (70%) were functionally good or normal at postoperative year 1. Before surgery, only 11 of 37 hips (30%) had been evaluated as functionally good or normal. Of 36 owners, 33 (91.6%) reported that they would have the procedure performed again if the circumstances were the same. From the good to excellent clinical results, we concluded that intertrochanteric osteotomy is a beneficial treatment for dogs with early-stage hip dysplasia.

Animals↗
PubMed1990

Nuclear changes in ovine luteal cells in response to PGF2 alpha.

Percentages of normal and apoptotic parenchymal cells, fibroblasts and endothelial cells in ovine corpora lutea at 12, 24 and 36 hr following administration of a luteolytic dose of PGF2 alpha were determined and compared to percentages for identical cell types in corpora lutea removed from control ewes on days 10 (n = 5) and 12 (n = 6) postestrus. In corpora lutea obtained from control ewes greater than or equal to 95% of nuclei examined were scored normal for each of the respective cell types with no difference (P greater than .05) observed between luteal tissue obtained on days 10 and 12 postestrus. Following treatment with PGF2 alpha there were significant (P less than .05) reductions in the percentages of nuclei scored normal. Compared to controls the percentage of endothelial cell nuclei scored normal was reduced at 12 hr following PGF2 alpha-treatment; however significant reductions in percentages of parenchymal and fibroblast nuclei scored normal were not evident until 24 and 36 hr, respectively. Consistent with the concept of apoptosis, nuclear condensation and/or margination indicative of apoptosis did not occur synchronously within a given cell type: i.e., irrespective of the time point examined some cells appeared normal, whereas others had undergone nuclear condensation and/or margination. A sequence of events to explain structural and functional changes that occur during luteolysis following the interaction of PGF2 alpha with specific receptors in large steroidogenic luteal cells is discussed.

Animals↗