Adrenal and ovarian sources of progesterone secretion in young female fallow deer, Dama dama

Progesterone regulates the endoplasmic reticulum-associated degradation and Unfolded Protein Response axis by mimicking the androgenic stimulation in prostate cancer cells

BACKGROUND

Today, androgen receptor (AR)-mediated signaling mechanisms in prostate cancer are intensively studied. However, the roles of other steroid hormones in prostate cancer and their effects on androgenic signaling still remain a mystery. Recent studies focused on the androgen-mediated regulation of protein quality control mechanisms such as endoplasmic reticulum-associated degradation (ERAD) and unfolded protein response (UPR) in prostate cancer cells. Present study, we investigated the action of progesterone signaling on ERAD and UPR mechanisms and analyzed the crosstalk of progesterone signaling with androgenic signal in prostate cancer cells.

METHODS AND RESULTS

The mode of action of progesterone on ERAD, UPR and AR signaling in prostate cancer was investigated by cell culture studies using LNCaP and 22Rv1 cells. To this aim qRT-PCR, western-blotting assay, immunofluorescent microscopy, nuclear fractionation and bioinformatic analysis were used. Our results indicated that progesterone positively regulates mRNA and protein levels of ERAD components in LNCaP cells. Also, it induced the IRE⍺ and PERK branches of UPR signaling. Progesterone receptor antagonist effectively antagonized the progesterone-induced responses. We also had similar results in 22Rv1 cells. Also, we tested the effect of the pharmacologically reducing of IRE⍺ and PERK signaling on progesterone-induced ERAD. Additionally, we determined the presence of putative progesterone response elements (PREs) in the promoter regions of ERAD members by bioinformatic tool. More strikingly, we found progesterone regulates AR signaling by modulating the nuclear transactivation of AR.

CONCLUSION

Herein, we defined that progesterone hormone positively regulates ERAD and UPR mechanisms in prostate cancer cells and that progesterone contributes to the molecular biology of prostate cancer by regulating androgenic signaling. Mode of Action of Progesteron on Androgen sensitive prostate cancer cells.

Regulation of uterine function during estrous cycle, anestrus phase and pregnancy by steroids in red deer (Cervus elaphus L.)

Steroid synthesis and production in ruminant uterus is not obvious, especially in seasonally reproduced. We compared steroid production by investigating enzymes involved in red deer uterine steroid metabolism in reproductive seasons. Blood and uteri (endometrium and myometrium) were collected post mortem from hinds on 4th day (N = 8), 13th day of the cycle (N = 8), anestrus (N = 8) and pregnancy (N = 8). The expression of cytochrome P450 aromatase (P450), 3 -beta-hydroxysteroid dehydrogenase (3β-HSD), 17 -beta-hydroxysteroid dehydrogenase (17β-HSD), aldo-keto reductase family 1 C1 (AKR1C1), estrogen receptor alpha (ERα), and progesterone receptors (PRs), were analyzed using real-time-PCR and Western Blotting. Plasma samples were assayed for 17-beta-estradiol (E2), progesterone (P4), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone (T4) concentrations by EIA. Hinds at the beginning of the estrous cycle, mainly in endometrium, were characterized by a high mRNA expression of 3β-HSD, AKR1C1, PRs and ERα, contrary to the expression in myometrium during pregnancy (P < 0.05). For P4, E2, and FSH, concentration was the highest during the 13th day of the estrous cycle (P < 0.05). Uterine steroid production and output in hinds as a representative seasonally reproduced ruminant occurred mainly during the estrous cycle and sustained in anestrus.

Opportunities and challenges associated with fecal progesterone metabolite analysis

Conventionally, plasma or milk progesterone evaluations are used to determine the reproductive status of female animals. Collection of such samples is often associated with difficulties of animal handling and restraint. Measurable quantities of progesterone metabolites are found in feces of animals. Their concentrations are known to be well correlated to plasma progesterone levels and are, therefore, used as non-invasive samples for assessing reproductive function in a wide range of animal species. Although the analysis of fecal progesterone metabolites has been widely accepted in many laboratories, several factors are known to affect the results from this valuable analytical technique. Some of these factors include storage/transportation media for fecal samples, type of solvent that is used for extraction of progesterone metabolites from feces, and the type and sensitivity of an assaying technique employed. Although fecal progesterone metabolites analysis is associated with some difficulties, it can effectively be used to monitor reproductive function in a wide range of animal species. This review aims to highlight the usefulness of fecal progesterone metabolite analysis as a non-invasive technique in monitoring reproductive function in animals. The article mainly focuses on the many opportunities and challenges associated with this analytical technique.

The impact of ovarian stimulation protocol on oocyte quality, subsequent in vitro embryo development, and pregnancy after transfer to recipients in Eld's deer (Rucervus eldii thamin)

Propagating genetically valuable individuals through oocyte collection, in vitro fertilization (IVF) and embryo transfer is critical to maintain sustainable populations of the endangered Eld's deer. The objectives of this study were to assess the impact of exogenous FSH injections on (1) the number and in vitro competence of oocytes collected and (2) the developmental potential of resulting IVF embryos after transfer into recipients during the breeding season (February-April). In a pilot experiment, estrus synchronization was conducted in three surplus females (using intravaginal progesterone-releasing devices, CIDRG for 14 days and injections of buserelin (a GnRH agonist). Five days after CIDR removal, ovaries were excised, minced and a total of 133 oocytes were recovered. Following in vitro maturation (IVM) and IVF, 63% of the oocytes formed embryos but only 5% reached the blastocyst stage. In a subsequent study, follicle numbers and diameters were compared between synchronized does stimulated with 0 or 80 mg FSH (-FSH and +FSH; n = 8 does in each group) and oocytes collected either by laparoscopic ovum pick-up or ovariectomy. FSH stimulation increased the main follicular diameter from 2-3 mm to 4-5 mm (P < 0.05) but not the oocyte number (∼20/donor) or the percentage of good quality oocytes (57%) regardless of the treatment. FSH stimulation did not either affect the percentage of cleaved embryos after IVF (25-35%; P > 0.05). Lastly, embryos at the 2-to 8-cell stage (from either + FSH or -FSH groups) were transferred into the oviducts of 11 synchronized recipients. With the +FSH embryos, three pregnancies failed between 90 and 120 days of gestation and two fawns that were born preterm (Days 215 and 224 of gestation) died at birth. In the -FSH group one healthy female fawn was born on Day 234 of gestation. This is the first report of a successful in vitro embryo production and subsequent birth of a live Eld's deer fawn. Further investigations are required to improve IVM/IVF success and the developmental potential of the embryos.

Seasonal luteal cyclicity of pubertal and adult red deer (Cervus elaphus)

Reproductive failure of rising-two-year-old (R(2)) hinds and seasonal misalignment between calving and pastoral feed production are two factors limiting reproductive productivity of farmed red deer hinds in New Zealand. This study aimed to better understand processes around female puberty and breeding seasonality by describing the potential breeding season (i.e., oestrous cyclicity) of three red deer genotypes. A total of 27 hinds born in December 2005, representing Eastern European (Cervus elaphus hippelaphus), Western European (C.e. scoticus) and F1 crossbred (C.e. hippelaphus×scoticus) red deer, were blood sampled thrice-weekly for 7-8 months (February-September/October) across two years spanning the potential breeding seasons as R(2)'s in 2007 (i.e., puberty) and as adults in 2008. Plasma progesterone profiles were used to construct breeding cycle histories for each hind. Four R(2) hinds failed to initiate oestrous cycles (i.e., puberty failure). The remaining R(2) hinds, including all F1 hinds, exhibited between two and seven oestrous cycles. F1 hinds were significantly earlier to initiate, and later to terminate, cyclic activity, resulting in a longer mean pubertal breeding season (139 days) than for Eastern (86 days) and Western hinds (86 days). However, the data for R(2) hinds are confounded by live-weight, with the F1 hinds being significantly heavier than other genotypes. There were significant correlations between live-weight and seasonality parameters in 2007. All hinds were cyclic as adults in 2008, exhibiting between four and nine oestrous cycles, and a mean breeding season duration of between 132 (Western) and 137 (F1) days. For adult hinds there were no significant genotype differences in cyclic onset and cessation timing, and no observable relationships between live-weight and any reproductive parameter. However, the mean dates for the onset of the breeding season for all genotypes in 2008 were 2-3 weeks later than normally expected for adult hinds in New Zealand. The reasons for this are unclear but may relate to chronic stress of frequent animal handling. The study has demonstrated that puberty in red deer hinds is associated with a shorter potential breeding season than for adult hinds, and that perturbation of breeding activity appears to be quite common, leading to incidences of puberty failure and possibly other aberrant cyclic events. Live-weight×genotype interactions may influence puberty but do not appear to be strongly expressed in adults. However, the relatively late onset of oestrous cyclicity in the adult hinds may be an artefact of the study that has masked genetic influences on seasonal breeding patterns.

Effect of method of blood sample collection on adrenal activity in farmed red deer and sheep following administration of ACTH

The effect of method of blood sample collection (automatic blood sampling equipment (ABSE) v. manual) on cortisol and progesterone concentrations was investigated in 20 farmed red deer hinds and 20 domestic sheep ewes following dexamethasone and exogenous ACTH administration. Ten animals were subjected to either automatic sampling or manual sampling via jugular venipuncture in 1 week, with the treatment groups reversed in the 2nd week. The ABSE was programmed to collect a blood sample, then deliver 2 mg dexamethasone, collect a further blood sample 120 min later and then inject 100 fig ACTH. Thereafter, samples were collected at 15-min intervals during a 2·5 h period (12 samples in total). In the manual injection and sampling treatment, four samples were collected: (1) before dexamethasone administration, (2) before ACTH administration, (3) 60 min after ACTH administration, and (4) 150 min after ACTH administration. The success rate of blood sampling with ABSE was 80%. The overall mean packed cell volume (PCV) from samples collected by ABSE from both hinds and ewes was significantly lower than that from samples collected manually (P < 0·01) and PCV declined with time in manually sampled animals (P < 0·01). Plasma cortisol concentrations peaked at 45 min after ACTH administration in sheep and deer. In sheep, there was a marked fluctuation in the plasma cortisol concentrations with time. Both deer and sheep showed a reduced cortisol response to ACTH during week 2 irrespective of sampling method suggesting down-regulation of the response to ACTH. Maximum mean plasma progesterone concentration was reached at 15 to 30 min after ACTH administration. No significant differences in cortisol and progesterone responses due to blood sampling method were found in animals receiving prior dexamethasone treatment. This demonstrates that the ABSE has the ability to be used to effectively conduct ACTH stimulation tests without the need to handle the animals during the test.

Induction of ovarian follicular wave emergence in wapiti (Cervus elaphus)

Two experiments were done to test the effects of treatments designed to electively induce ovarian follicular wave emergence in wapiti for the purpose of group synchronization. In Experiment 1, hinds were assigned randomly to three groups and given saline im (controls; n=5), 5mg of estadiol-17beta im (n=4), or 5mg estradiol-17beta plus 100mg progesterone im (n=5). In Experiment 2, hinds were assigned randomly to two groups and given no treatment (controls; n=6), or transvaginal ultrasound-guided follicle ablation (n=7). In both experiments, ovarian follicular dynamics were monitored by daily transrectal ultrasonography from Day 0 (day of treatment) to Day 9. In Experiment 1, blood samples were collected at each examination for measurement of serum concentrations of progesterone and FSH. Both experiments were conducted during the late anestrous period (July and August). The mean (+/-S.E.M.) day of wave emergence did not differ between the control and estradiol alone groups, but tended to be later in the estradiol plus progesterone group Day 4.0+/-0.7, Day 3.5+/-0.3, and Day 5.2+/-0.2, respectively; P=0.06). The interval from treatment to wave emergence was less variable in the estradiol plus progesterone group (P<0.05) and tended to be less variable in the estradiol-alone group (P=0.07) than in the control group. The day of wave emergence was more variable (P<0.05) and tended to be later (P=0.10) in the control group compared to the ablation group (Day 2.5+/-0.8 versus Day 1.4+/-0.2). All three treatments were effective in synchronizing ovarian follicular wave emergence among a group of wapiti hinds. Follicle ablation may be an alternative method for synchronization of follicular waves in estrus synchronization and superstimulatory protocols.

Successful in vitro culture of early cleavage stage embryos recovered from superovulated red deer (Cervus elaphus)

Three separate embryo culture systems were evaluated for their ability to support development of early cleavage stage red deer (Cervus elaphus ) embryos: ligated sheep oviducts (Treatment A); cervine oviduct epithelial monolayer in TCM 199 + 10% deer serum (Treatment B); synthetic oviduct fluid + 20% human serum at 7% O(2) atmosphere (Treatment Q. In addition, 2 superovulation protocols were compared for their efficacy in producing early cleavage stage embryos. Twenty red deer (2 to 7 yr old) were synchronized in April with intravaginal CIDR devices for 12 d. All animals received a total of 0.4 units of ovine FSH administered in 8 equal doses, 12 h apart, beginning 72 h before removal of CIDR devices. The deer additionally received 200 IU PMSG, either with the first FSH injection (Group 1, n = 10) or with the last FSH injection (Group 2, n = 10). Hinds were placed with fertile stags following withdrawal of CIDR devices. Ova were collected by surgical recovery 63 h post CIDR removal. At the time of collection, animals in Group 2 had a significantly greater mean (+/- SEM) ovulation rate (11.2 +/- 2.4 vs 5.3 +/- 2.4), with more animals responding to treatment (>1 ovulation), than the animals in Group 1 (10/10 vs 4/10). Late in the breeding season (June), 10 additional red deer (Group 3, Experiment 2) were superovulated using the same protocol as for the deer in Group 2, with ova collection advanced by 24 h. Mean (+/- SEM) ovulation rate was 6.4 +/- 1.2 with 9 10 animals responding. Ova recovery did not differ among the groups (range 73 to 87%). Superovulation treatment did not affect cultured embryo development to the morula/blastocyst stage. Furthermore, there was no difference among the 3 culture systems in their support of development either to the morula (range 50 to 58%) or to the blastocyst (range 22 to 26%) stage. After laparoscopic transfer of 4 morula/blastocyst embryos to recipient red deer (2 from Treatment B and 2 from Treatment C) 2 live calves were born from embryos cultured in Treatment B.

Steroid hormone secretion during the ovulatory cycle and pregnancy in farmed Alaskan reindeer1

Seasonal endocrine changes in 5 non-bred and 10 pregnant Alaskan reindeer have been documented. Blood samples were collected from early September until early May, spanning the breeding season, gestation, or the anovulatory period. Plasma was analyzed by RIA for progesterone (P4), estradiol-17beta, estrone, and estrone sulfate. Elevated P4 in 80% of the reindeer at the onset of the study indicated that ovarian activity had been initiated. The median date for the onset of the first recorded full-length ovulatory cycle was September 23. In nonbred reindeer, the mean ovulatory cycle length from September to May was 24 +/- 1 d (range 18 to 29 d). Nonbred females continued to cycle throughout the winter, displaying 6 to 8 ovulatory cycles after the beginning of blood sampling. Cycle length (mean 22 to 24 d) did not vary between individuals (P = 0.170) or over the course of the winter (P = 0.244). In early April, ovulatory cycles ceased with normal demise of the corpus luteum in 2 females, whereas the remaining 3 females formed apparently persistent corpora lutea. Natural service breeding occurred between September 10 and October 2, and P4 profiles indicated that all breeding females conceived to the first mating. Concentrations of P4 rose steadily after conception and remained elevated throughout gestation, with mean concentrations not varying significantly (P = 0.104) from 4 to 28 wk of gestation. Estrogens all followed patterns similar to each other, remaining at baseline concentrations until approximately 24 wk of gestation and rising coincidently as P4 declined just before parturition. There was a continual overlap throughout the winter in peak P4 concentrations observed in cycling and pregnant reindeer. Calving occurred between April 8 and May 2, resulting in a mean gestation length of 211 +/- 2.2 d (range 198 to 221 d). Information from this study can be used by Alaskan reindeer producers to improve management and profitability of reindeer production.

Plasma progesterone response following ACTH administration during mid-gestation in the pregnant Brahman heifer

Previous reports of adrenal progesterone (P4) contributions during late gestation in cattle, and ACTH-induced P4 responses in the non-pregnant heifer, prompted a retrospective investigation to evaluate the plasma P4 response and the relative ratio of plasma cortisol (CT) to P4 following ACTH administration during mid-gestation in pregnant Brahman heifers. Twenty-three pregnant (139.0 +/- 5.0 days of gestation) Brahman heifers received one of the following treatments: 0 (saline; n = 5), 0.125 (n = 4), 0.25 (n = 5), 0.5 (n = 4), or 1.0 (n = 5)IU of ACTH per kg BW. Blood samples were collected at -15 and -0.5 (time 0), 15, 30, 45, 60, 75, 105, 135, 165, 195, and 255-min post-ACTH challenge. Plasma P4 and CT were quantified by RIA. Pre-ACTH P4 did not differ (P > 0.10) among ACTH treatment groups (pooled, 12.1 +/- 0.6 ng/mL). Among peak P4 values at 15-min post-ACTH infusion, control P4 (9.6 +/- 1.2 ng/mL) tended to be lower (P < 0.07) than 0.5 IU ACTH-treated heifers (13.3 +/- 1.1 ng/mL); and were lower (P < 0.02) than 0.25 and 1.0 IU ACTH-treated heifers (14.7 +/- 1.1 and 22.2 +/- 3.7 ng/mL, respectively). During the primary P4 response period (0 to 75-min post-ACTH), the area under the curve (AUC) was greater (P < 0.05) for 1.0 IU ACTH-treated heifers than all other groups. The CT:P4 ratios were lower (time x treatment, P < 0.01) for control heifers than all ACTH-treated heifers. Among ACTH-treated heifers, CT:P4 ratio response and CT:P4 ratio AUC were similar (P > 0.10) following ACTH challenge. In conclusion, acute increases in ACTH elevated plasma P4, likely of adrenal origin, in mid-gestation pregnant heifers, while the CT:P4 ratio (relative output) remained constant irrespective of ACTH dose (0.125-1.0 IU). Whether ACTH-induced increases in P4 in pregnant animals are of physiological significance (e.g., an accessory role in the maintenance of pregnancy during periods of acute stress) remains to be determined.

Energy level in winter diets of Fallow deer: effect on plasma levels of insulin-like growth factor-I and sex ratio of their offspring

To determine the effect of dietary energy level in the first winter on subsequent puberty onset, pregnancy, growth, and secretion of progesterone and insulin-like growth factor-I (IGF-I) in Fallow deer, prepubertal deer were fed either a high (H) or a low (L) energy diet in a randomised complete block design. June-born female Fallow deer were fed ad libitum either 12.5MJ/kg DM (H, n=29) or 10MJ/kg DM (L, n=29) in pelleted rations once per day during the winter (approximately 4-10 months of age) preceding puberty. Blood samples were collected twice weekly during the peripubertal period. During the winter feeding period, DM intake was similar for both groups but average daily gain was greater (P<0.05) for deer fed the H versus L diet. Onset of puberty was not affected (P>0.10) by dietary treatment. Concentrations of progesterone in plasma did not differ (P>0.10) between dietary treatments before or after puberty, increasing after puberty in both groups, and reaching maximal levels 8-12 days after the onset of puberty. Concentrations of plasma IGF-I increased (P<0.05) before puberty in both groups reaching maximal levels 3-4 days before the onset of puberty but did not differ (P>0.10) between H and L diets before or after puberty. Of the 28 does fed the H diet that calved, 75% of the calves born were male versus 46% in the L diet (P<0.05). In conclusion, increased plasma IGF-I concentrations were associated with the onset of puberty in Fallow deer regardless of the level of dietary energy intake during the preceding winter. Increased dietary energy during winter does not alter pregnancy rates but does alter sex ratio of calves born.

Effects of adrenocorticotrophin (ACTH) and progesterone on luteinising hormone (LH) secretion in recently castrated rams

The goal of the present study was to determine whether ACTH and progesterone have any effect on LH secretion and pulse frequency in recently castrated rams. Six 2-year-old Corriedale rams were castrated in the winter. The day before castration, blood samples were taken in order to establish the precastration LH levels. The rams were divided into an untreated group (group U: n = 2) and a treated group (group T: n = 4). The first treatment consisted of the i.v. administration of 0.5 mg of ACTH on day 20 post-castration, immediately after the first sample had been taken. During the second treatment, subcutaneous progesterone implants were given to group T for 5 days. Control samplings were performed one week before each treatment. Prior to castration, the testosterone levels were low, while after castration they were below the detection limit of the assay. Cortisol and progesterone concentrations were basal before castration in all of the animals and after castration in group U and also in the control samplings for group T. ACTH treatment caused a significant increase in both cortisol and progesterone levels for 3 h (P < 0.001). Progesterone implants raised progesterone levels in group T, but cortisol levels remained basal. Before castration, all animals had low LH levels and hardly any pulse activity was seen. After castration, both the number of LH pulses and the mean LH production increased significantly in all of the animals (P < 0.01). During the ACTH trial, LH pulse frequency was significantly reduced for the first 4 h following ACTH administration (P = 0.013), however, no such differences occurred in the prior control period. No effect was seen on mean LH concentration during the ACTH treatment. Progesterone treatment did not have any effect on either the number of LH pulses nor on LH concentrations (P > 0.05).

Effects of post-ovulatory food deprivation on oviductal sperm concentration, embryo development and hormonal profiles in the pig

Nutrition is one of the multiple factors that modulate reproduction in animals. The effect of 48 h food deprivation on reproductive and metabolic hormonal changes in relation to cleavage rates was studied. Insemination of 15 sows was performed 20-10 h prior to expected ovulation and ova were recovered at slaughter 65-91 h post ovulation. Blood samples were collected every second hour, beginning from the time of insemination until slaughter, for measurements of progesterone, cortisol, the prostaglandin F2alpha metabolite (15-keto-13,14-dihydro-PGF2alpha) and insulin levels. The embryos from the food-deprived sows (D-group) had fewer accessory spermatozoa in their zona pellucida (ZP) compared with the control sows (C-group). A lower cleavage rate of the embryos in the D-group compared with the C-group was detected. Plasma progesterone, cortisol and prostaglandin F2alpha metabolite levels were significantly higher in the D-group compared with the C-group. Food deprivation is associated with changes in reproductive and metabolic hormones that might lead to changes in the oviductal environment, culminating in a lower cleavage rate of the embryos and presence of fewer viable spermatozoa in the reservoir.

Early pregnancy detection and the hormonal characterization of embryonic-fetal mortality in fallow deer (Dama dama)

The objectives of this investigation were to 1) determine serum concentrations of progesterone (P4), estrone sulfate (E1S) and pregnancy-specific protein B (PSPB) from estrus synchronization through mid-gestation in the fallow doe (Dama dama) and 2) characterize the hormonal profiles of does whose embryos or fetuses died in utero. Ten fallow does were synchronized for 14 d with an intravaginal P4-releasing device (CIDR) and were naturally mated after CIDR removal. Blood samples were collected at CIDR insertion, CIDR removal and at intervals through Day 203 post-CIDR removal for analysis of P4, E1S and PSPB by radioimmunoassay (RIA). Ultrasonography was performed on Days 49 and 69 post-CIDR removal. Serum P4 at the time of CIDR insertion was 4.8 +/- 0.6 ng/ml, and at CIDR withdrawal it was 6.2 +/- 0.3 ng/ml. Concentrations of E1S and PSPB were nondetectable at CIDR insertion. Serum E1S was highest at Day 93, and PSPB was first detectable in pregnant does at Days 27 to 30 post-CIDR withdrawal. Ultrasonography on Day 49 revealed that 6 does were pregnant, 2 were not pregnant and 2 others were diagnosed originally as early pregnant. At Day 69, ultrasonography revealed that 6 does (60%) were pregnant and 4 (40%) were not. A comparison of the ultrasonographic and hormonal data indicated that the 2 does diagnosed as early pregnant on Day 49 had conceived but had lost the pregnancy. A third doe which was pregnant on Day 69 lost the fetus later in gestation. Hormonal profiles of does whose embryo or fetus had died were characterized by erratic P4 and E1S profiles, with PSPB becoming undetectable in the 3 does by Days 49, 65 and 80 post-CIDR removal. These data 1) demonstrate the timing for the collection of serum samples for determining early pregnancy in fallow does using 3 hormonal methods and 2) characterize the hormonal profiles of 3 fallow does with embryonic-fetal loss.

Effect of blood sampling and administration of ACTH on cortisol and progesterone levels in ovariectomized zebu cows (Bos indicus)

Four zebu cows were bilaterally ovariectomized through lateral laparotomy. Three months after ovariectomy, blood samples were collected by jugular venipuncture daily for 5 consecutive days prior to a single injection of ACTH to establish baseline concentrations of cortisol and progesterone. Baseline concentrations of cortisol and progesterone were 31 +/- 5 nmol/L and 0.3 +/- 0.01 nmol/L, respectively. On the day of ACTH treatment the cows were allowed to rest for 2 h to reduce the stress of cannulation before the sampling period started. Blood samples were collected every 30 min from 2 h before until 2 h after the injection of 6 micrograms ACTH and hourly between 2-6 h after ACTH injection. A significant increase was observed in cortisol secretion from 90 min before until 120 min after ACTH injection. No significant increase was observed in progesterone secretion before ACTH injection. After ACTH injection progesterone was significantly elevated for 120 min. Four weeks after the ACTH treatment the cows were cannulated again and blood samples were collected following the same bleeding schedule used during the ACTH experiment. Instead of ACTH a saline injection was given via the catheter. A significant increase in cortisol concentration was recorded 90 min before saline injection. This increase was not accompanied by an elevation in progesterone concentration. No significant changes were observed in cortisol and progesterone levels after saline injection. When cortisol was added to a plasma pool having a progesterone concentration of 0.3 nmol/L and a cortisol concentration of 25.4 nmol/L and assayed for progesterone in 2 different assays no increase in progesterone concentration was observed. We conclude that the adrenal glands can be an extra-ovarian source of progesterone during stress in Zebu cows.

Plasma cortisol responses to remote adrenocorticotropic hormone (ACTH) infusion in free-ranging red deer (Cervus elaphus)

A remote infusion and blood collection device (Dracpac) was used on free-ranging red deer stags to deliver i.v. a range of ACTH1-24 doses and collect blood for cortisol determination. In Experiment 1, conducted in September, saline and 1, 4, and 16 IU ACTH/100 kg bodyweight were infused (n = 5-7 per treatment). In Experiment 2 (November), 16 and 64 IU ACTH/100 kg were infused (n = 5 per treatment); and the response of animals to restraint was also assessed (n = 6). Pre-infusion concentrations of plasma cortisol were low (mean 6.5 +/- 1.0 ng/ml), and unaffected by infusion of saline. ACTH significantly elevated plasma cortisol concentrations, with mean peak concentrations occurring 20-40 min postinfusion. Duration of the response was dose dependent, ranging from 80-160 min. With increasing doses of ACTH, maximal peak heights plateaued at approximately 40 and 60 ng/ml in September and November, respectively; whereas the areas under the curves tended to increase. The minimum dose of ACTH that resulted in a maximal peak cortisol response was 4 IU. The maximum peak height of the cortisol response to 16 IU tended to be higher (P < 0.10) in November compared with September, suggesting that adrenal responsiveness may change over this period. The adrenal response to a 16-IU ACTH challenge in Experiment 2 resulted in similar plasma cortisol concentrations to an acute stress event (restraint). Four IU/100 kg ACTH i.v. is recommended as an appropriate dose for ACTH infusion studies in red deer stags. When used in conjunction with the Dracpac technique, it becomes a stress-free, repeatable procedure for assessing aspects of adrenal cortex physiology in free-ranging deer.

Artificial insemination, hybridization and pregnancy detection in sika deer ()

Artificial insemination (AI) was performed on sika hinds (Cervus nippon ) receiving various dosages of pregnant mare serum gonadotropin (PMSG; Year 1: 0, 50 and 100 IU; Year 2: 100 and 150 IU) and using semen collected from elk and 1 2 elk x 1 2 sika stags. The time from synchronization device removal (CIDR vs norgestomet) to estrus was determined through observations of mounting activity. Methods for pregnancy detection, serum progesterone (P4), estrone sulfate (E1S), pregnancy-specific protein B (PSPB) and ultrasonography, following AI (Year 1: AI, Days 28 and 48 after AI; Year 2: AI, Days 42, 53 and 100 after AI) and a 90-d natural breeding season were investigated. From available production data, body weights were compared among sika and 1 4 elk x 3 4 sika hybrids relative to age. Pregnancy rates tended (P < 0.10) to differ relative to PMSG treatment and sire; administration of 0 IU PMSG resulted in fewer hinds becoming pregnant to AI than 50 or 100 IU of PMSG. Hinds receiving 100 IU of PMSG had higher (P < 0.05) pregnancy rates than hinds receiving 150 IU PMSG. Time to standing estrus did not differ (P > 0.10) between the CIDR and norgestomet groups. Pregnancy rates 50 d after a 90-d breeding season were similar (P > 0.10) between ultrasound (70.9%) and PSPB (61.6%). Serum P4 after 90 d in breeding groups and 50 d after stag removal were higher (P < 0.05) for pregnant than open hinds. Pregnancy rates (Year 1) 48 d after AI were similar (P > 0.10) between ultrasound (49.0%) and PSPB (37.3%). Serum P4 28 and 48 d after AI were higher (P < 0.05) for pregnant than open hinds. Serum E1S was higher (P < 0.01) for pregnant than open hinds 48 d after AI. Pregnancy rates (Year 2) 100 d after AI did not differ (P > 0.10) between ultrasound and PSPB (66.7%). Serum P4 was higher (P < 0.03) in pregnant than open hinds at 42, 53 and 100 d after AI. At 100 d after AI, pregnant hinds had higher (P < 0.002) serum E1S than open hinds. At 6 to 8 and 11 to 13 mo of age, 1 4 elk x 3 4 sika males tended (P < 0.08) to be heavier than sika males, while 1 4 elk x 3 4 sika females were heavier (P < 0.05) than sika females at all ages. In summary, this study documents the use of AI and methods for pregnancy detection in sika hinds as well as preliminary information regarding the production of elk-x-sika hybrids.

Influence of prenatal photoperiod on postnatal plasma concentrations of progesterone and prolactin in female red deer (Cervus elaphus) reared in constant equatorial photoperiod

Prenatal photoperiod influences postnatal prolactin secretion and the timing of reproductive development in male red deer reared from birth in a constant equatorial photoperiod (12:12 light:dark). The present trial investigated whether a similar phenomenon occurs in female red deer. Female deer whose mothers had been exposed for the last 14 weeks of gestation to long (group L, 18:6 light:dark) or short day length (group S, 6:18 light:dark) were kept from birth in constant equatorial day length with food available ad libitum. Both groups showed similar live-weight gain to 90-100 weeks of age. Blood samples taken once or twice weekly were analyzed for progesterone and prolactin. Progesterone concentrations indicated that there was no difference between the groups in the timing of the first incidence of ovarian (luteal) activity, which occurred at a normal or late age for natural puberty (67 weeks or older). Only one individual per group exhibited normal repeated luteal cyclicity since there was a high incidence of irregular or abnormal luteal function. Plasma prolactin concentrations at birth were higher in group L than group S (P < 0.001). Thereafter, although the mean and peak values did not differ significantly between the groups, there was a significant difference in the pattern of secretion; deer in group L showed significant clustering of prolactin peaks (P < 0.01) at a mean age of 48 weeks, whereas deer in group S showed a random distribution of peaks. Therefore, for female red deer raised in constant equatorial photoperiod, prenatal long day lengths did not advance timing of puberty.(ABSTRACT TRUNCATED AT 250 WORDS)