Qiviut cortisol reflects hypothalamic-pituitary-adrenal axis activity in muskoxen (Ovibos moschatus).

Muskoxen (Ovibos moschatus) are increasingly exposed to a broad diversity of stressors in their rapidly changing Arctic environment. There is an urgent need to develop validated tools to monitor the impact of these stressors on the hypothalamic-pituitary-adrenal (HPA) axis activity of muskoxen to help inform conservation actions. Here, we evaluated whether muskox qiviut (dense wooly undercoat) cortisol accurately reflects changes in HPA axis activity. Two repeated pharmacological challenges, involving weekly administrations of saline (control group) or adrenocorticotropic hormone (ACTH) during five consecutive weeks, were done on captive muskoxen, in winter (no hair growth) and summer (maximum hair growth). Pre-challenge qiviut cortisol levels were significantly higher in the shoulder than in the neck, but neither differed from rump concentrations. Qiviut cortisol levels significantly increased (p < 0.001) in response to the administration of ACTH during the hair growth phase, but not in the absence of growth (p = 0.84). Cortisol levels in the qiviut segment grown during the summer challenge increased significantly over a six-month period in the ACTH-injected muskoxen with a similar trend occurring in the control animals. Finally, cortisol levels in shed qiviut were significantly higher and not correlated to those of fully grown qiviut shaved three months earlier. Our results show that cortisol is deposited in qiviut during its growth and that qiviut cortisol can thus be used as an integrated measure of HPA axis activity over the period of the hair's growth. Differences in qiviut cortisol across body regions, significant differences in qiviut segments over time, and differences between shed qiviut versus unshed qiviut, highlight the importance of consistent design and methodology for sample collection and analyses in order to account for sources of variation when using qiviut cortisol as a biomarker of HPA axis activity in muskoxen.

Depo-Provera increases neural activity in the central amygdala of reindeer bulls.

Reindeer bulls are difficult to manage and dangerous to handlers during the rutting period. Progesterone agonists have been used anecdotally in the field to favorably influence behavior, but effects on reproductive signaling have not been determined. The objective of this study was to determine the effects of Depo-Provera (medroxyprogesterone acetate) on neural activity in the amygdala of reindeer bulls in the early (n = 4) and full (n = 4) rut. Treated bulls (n = 4) were injected with a single injection of Depo-Provera (400 mg i.m.) approximately 2 wk before rut was initiated. Control bulls were untreated. Bulls were exsanguinated and brains collected. Neural activity in the amygdala was determined using c-fos immunohistochemistry. Neural activity did not differ by treatment (P ≥ 0.5), collection period (P ≥ 0.5), or their interaction (P ≥ 0.3) in the medial and cortical amygdala nuclei. A treatment × time interaction (P = 0.009) was observed in the central amygdala. The amygdala nuclei are interconnected allowing for integration of sensory stimuli with a direct connection between the medial amygdala and the olfactory bulb. The central amygdala is responsible for alerting, fear, and initiating a state of arousal towards nonspecific stimuli in the surrounding environment. In wildlife, the central amygdala has a role in recognizing threats in the environment such as predators. During the rut, bulls normally have a decreased sense of fear and elevated aggressive behavior with Depo-Provera treatment seemly able to diminish that aggression. Although it is unlikely that this observed change in neural activity fully explains the decreased aggressive behavior noted in bulls treated with Depo-Provera, neural networks of aggression include the amygdala. It is possible that further changes in c-fos activity will be noted in other areas of the brain known to be necessary for processing social cues. Bulls treated with Depo-Provera maintain sexual interest and have offspring. Depo-Prevera increases the neural activity within the central amygdala and may partially account for their altered aggressive behavior during the rut.

Gestation length in farmed reindeer.

Reindeer (Rangifer tarandus tarundus) are the only cervids indigenous to the arctic environment. In Alaska, reindeer are a recognized agricultural species and an economic mainstay for many native populations. Traditionally raised in extensive free-ranging systems, a recent trend toward intensive farming requires a more in-depth knowledge of reproductive management. Reported gestation length in reindeer varies, ranging from 198 to 229 d in studies performed at the University of Alaska Fairbanks. A switchback study that manipulated only breeding date demonstrated a mean increase in gestation length of 8.5 d among females bred early in the season. The negative correlation between conception date and gestation length is consistent with reindeer research at other locations and reports of variable gestation length in a growing number of domestic and non-domestic species. This paper reviews the phenomenon in reindeer and discusses some of the factors known to affect gestation length as well as possible areas for future research.

Variation in gestation length among captive reindeer (Rangifer tarandus tarandus).

An estimated 90% of reindeer females are mated in a 10- to 21-d interval and give birth in an equally synchronized manner. Reported gestation length in reindeer is highly variable (range, 203 to 240 d), almost twice the reindeer estrous cycle length. Previously, we identified a significant, negative relationship between gestation length and conception date in a small group of reindeer. In the current study, the negative relationship was investigated in a switchback design, where reindeer were divided into two groups synchronized for early and late mating over a 2-yr trial. Regression analysis of 11 paired observations produced a negative (P<0.001) association between gestation length and conception date (slope= -0.31). Dam weight at breeding and prior to parturition, calf birth weight, and calf sex were not significant variables in the regression. Regression analysis of a larger data set from two University of Alaska Fairbanks reindeer herds, where conception date (verified by systemic progesterone) and gestation length were recorded (historical data set), supported previous conclusions (n=70; slope= -0.37; P<0.001). Although the calf sex ratio did not differ with gestation length, there was a positive relationship (r(2)=0.19; P=0.014) between male birth weight and gestation length in the larger data set. The negative relationship between conception date and gestation length enhanced calving synchrony, though the limits of gestation plasticity and underlying mechanisms are not clear. The potential role of photoperiod on early embryonic development is discussed.

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

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.

The male effect, mounting behavior, and the onset of estrus in farmed muskoxen.

Muskox farming is an emerging industry in Alaska. For such an endeavor to succeed, it is necessary to develop fundamental husbandry tools specifically for this species. This study examined the role of the bull in the onset of seasonal ovarian activity and the synchrony of estrus and tested the efficacy of a radiotelemetric estrus detection system. Twenty parous female muskoxen, ranging in age from 4 to 15 yr, were divided into three groups (balanced by age and body weight). Groups received early bull exposure (EBE; August 1, n = 7), late bull exposure (LBE; August 22, n = 6), or remained physically isolated from a bull (NBE; n = 7). Just before bull introduction, radiotelemetry transmitters were attached to the rump of muskox cows in the EBE and LBE groups. Plasma samples were collected from all the cows twice weekly and analyzed for progesterone (P4). The mean date of onset of seasonal ovarian activity was earlier in the EBE and LBE groups than in the NBE group (P < 0.001) and was earlier in EBE (P < 0.021) than in LBE. All EBE and LBE cows conceived to the first fertile cycle, giving 100% fertility. The time interval for the onset of ovarian activity between the first and last cow within each group was 7 d in the EBE group, 12 d in the LBE group, and 24 d in the NBE group. Radiotelemetry correctly identified estrus 95% of the time (18 of 19 instances). Mean length of estrus for each cow, calculated from the time of first mount until last mount, was 771 +/- 98 min (range = 4 to 1,508 min). Mean number of mounts during estrus was 8.89 +/- 1.29 (range = 3 to 25 mounts). Length of estrus at the first short cycle did not differ from the length of the first fertile estrus between, or within, individuals. Estrous behavior was initiated more frequently during the night (2300 to 0500; P < 0.05). Bull introduction can be used as a simple, low-cost management tool for synchronizing estrus in farmed muskoxen. Radiotelemetry was an effective tool for identifying breeding behavior in this species.

Reindeer bull introduction affects the onset of the breeding season.

Reindeer are seasonally polyestrus, short day breeders, with estrous cycles of approximately 20 days in length. The objective of this study was to investigate the effects of reindeer bull exposure on the onset of the reindeer cow breeding season and to investigate whether cows with calving experience responded differently than cows with no previous reproductive experience. During year 1, blood samples were collected weekly beginning 14 July and continuing until 15 September (n = 8) or 30 September (n = 8) in order to determine the onset of the breeding season, based on ovarian function, with no bull present. Plasma was stored frozen for later assay of progesterone (P(4)) following the conclusion of sample collection. Eight randomly selected cows were allowed to breed with a bull during year 1. The mean onset of ovarian activity in the first year was 15 September (range: 8-29 September). The bull was removed from cows more than 2 months prior to the start of the experimental period during year 2 and housed at a separate facility approximately 2 km distant. Blood samples were collected during year 2 from 14 cows 3x weekly beginning on 11 August (day 1) and continuing until 29 September (day 50) and plasma was stored frozen for later assay of P(4) following the conclusion of sample collection. On day 6, cows were divided into two groups such that group 1 (early bull exposure; EBE), consisted of four cows that had calved the previous spring and four cows that had no reproductive experience (n = 8). Group 2 (late bull exposure; LBE), consisted of three cows that had calved the previous spring and three cows that had no reproductive experience (n = 6). EBE experienced bull introduction on day 13, 23 days earlier than the average onset of ovarian activity during year 1. LBE experienced bull introduction on day 46, 10 days later than the average onset of ovarian activity during year 1. Progesterone concentrations were analyzed by ANOVA procedures for repeated measures. Bull presence was not requisite for the onset of ovarian activity during either year. Previous reproductive status had no effect on the onset of ovarian activity within EBE (P = 0.61) or within LBE (P = 0.92). Time of bull introduction had a significant effect on the onset of ovarian activity when EBE was compared to LBE (P<0.001). The first sustained increase in mean P(4) concentration above 1 ng/ml occurred on day 25 in EBE reindeer and day 41 in LBE reindeer. EBE reindeer initiated ovarian activity 12 days after bull introduction while LBE reindeer initiated ovarian activity 5 days before bull introduction. All cows penned with the bull conceived during both breeding seasons, demonstrated by production of live calves during the subsequent spring. Cows bred during year 1 all calved within a 9 day-period. During year 2, EBE displayed a more synchronous calving period compared to LBE (P<0.05). Results indicate that bull management affects the onset of the breeding season in reindeer cows, regardless of previous reproductive experience.

Cytotoxicity of 2-aldo- and 2-ketopyridine-N(4)-substituted thiosemicarbazones and mode of action in human Tmolt4 cells.

The 2-aldo- and 2-ketopyridine-N(4)-substituted thiosemicarbazones and their copper complexes demonstrated potent cytotoxic activity against a series of murine and human suspended cultured tumor cells. Selected compounds were active against the growth of cultured cells from solid human tumors, i.e. Mck-7 breast effusion, lung A549 and lung MB-9812, bone SOS-2 and clear cell Caki renal tumor. In Tmolt4 T cell leukemia cells the compounds inhibited the syntheses of DNA, RNA and protein over 60 min at 25 to 100 microM. Multiple target sites in nucleic acid metabolism were suppressed by the agents, i.e. DNA polymerase alpha, ribonucleoside reductase, dihydrofolate reductase, de novo purine synthesis, thymidylate synthetase and nucleoside kinases. The total effects of the agents on DNA metabolism led to the reduction of deoxyribonucleotide pools as well as DNA fragmentation.

Fiber characteristics of qiviut and guard hair from wild muskoxen (Ovibos moschatus).

In response to increasing commercial interest and the high market value of qiviut (the downy underwool of the muskox), we have employed standards and measurements used in the wool and cashmere industries to describe qiviut fiber characteristics. Fleece samples (qiviut with guard hair) were shaved from the midshoulder of 299 wild muskox hides of known sex and age (1, 2, 3, and 4+ yr) during the Banks Island, Canada, muskox harvest in November 1997. Samples were analyzed for fiber diameter distribution of raw fiber and qiviut, scoured and qiviut yields, and lengths of guard hair and qiviut fiber. We found a sex x age interaction for average fiber diameter (AFD) in raw fiber (P= 0.002) and qiviut (P < 0.001) only. Adult males had significantly coarser AFD than females (21.5 microm, males vs 20.1 microm, females and 18.2 microm, males vs 17.5 microm, females) for raw fiber and qiviut, respectively. Qiviut AFD from yearlings was 1.7 microm finer than the AFD of adult qiviut. Fiber diameter distribution (SD) decreased with age in the raw sample (P < 0.003) and qiviut (P < 0.001) and qiviut SD was greater (P < 0.001) in males than in females. Qiviut theoretical yield (% mass of fibers < or = 30 microm) increased (P < 0.001) with age, and females had higher theoretical yields than males (P < 0.001). Scoured yield did not vary between sexes in any age class and averaged 93.3%. Qiviut staple length did not differ with either age or sex. In summary, differences between the sexes were small up to the 3rd yr, and these differences were not likely to be of commercial importance. However, considering that AFD is a primary commercial criterion of value, AFD changes from 16.5 microm in yearlings to 18.2 microm in adults and from 17.5 microm in adult females to 18.2 microm in adult males would be expected to result in significant differences in commercial value.

Cytotoxicity of rhenium(I) alkoxo and hydroxo carbonyl complexes in murine and human tumor cells.

The rhenium(I) alkoxo/hydroxo carbonyl complexes were shown to be very potent in suspended tumor cell lines in suppressing growth but were more selective in inhibiting the growth of cultures from solid tumors. Their mode of action in L1210 lymphoid leukemia cells indicated that they were not alkylating agents but interfered with nucleic acid metabolism at multiple enzyme sites, e.g. dihydrofolate reductase, PRPP-amido transferase, thymidine kinase, with DNA strand scission after 60 min incubation. These compounds did not function mechanistically exclusively as cisplatin derivatives causing intrastrand linkages of DNA but rather they mimicked the metal complexes of aminecarboxyboranes, furan oximes, N-substituted thiosemicarbazones, trifluoromethyl borons and ferratricarbadecarbanyl complexes acting as antimetabolites.

Fetal growth in muskoxen determined by transabdominal ultrasonography.

A 5 MHz commercial sector scanner was used to monitor 13 muskox pregnancies and establish normal fetal growth curves. Examinations were carried out between 40 and 197 days of gestation and pregnancy could be detected throughout the period. Early pregnancies were found by scanning lateral to the udder but as pregnancy progressed the fetus was found closer to the dam's umbilicus. Measurements of cranial and abdominal diameters taken at about two week intervals in seven uncomplicated pregnancies in four cows were used to construct fetal growth curves. These can be reliably used in the reproductive management of muskoxen. In addition a series of regressions based on measurements of the fetuses of muskoxen killed in the Arctic are provided. These allow cranial and abdominal diameters to be related to fetal weight and crown-rump length.

Endocrine changes and luteal morphology during pregnancy in muskoxen (Ovibos moschatus).

Progesterone, oestradiol and oestrone were measured in plasma from four captive muskoxen during three consecutive pregnancies (1983-1984, 1984-1985 and 1985-1986). Jugular blood samples were collected weekly (1983) or on an alternating 3:4 day schedule (1984-1986) during the first 12-15 weeks and last 6-10 weeks of pregnancy. Sampling during mid-pregnancy was at intervals of 2 weeks (1983 and 1985) or 1 week (1986). Duration of gestation was about 34 weeks (235 +/- 4 (SD) days (n = 10), range 230-242 days). Progesterone remained at concentrations similar to those found during the luteal phase of the oestrous cycle for the first 10-12 weeks (mean +/- SEM 1.6 +/- 0.1 ng ml-1) after which it rose to a peak (mean 5.5 +/- 0.65 ng ml-1) between weeks 12 and 20. In all ten pregnancies progesterone concentrations declined dramatically between weeks 20 and 22 to luteal phase values where they remained until parturition. The decline was accompanied by an increase in oestradiol and oestrone concentrations which reached mean peak values of 199.23 +/- 87.23 pg ml-1 and 980.48 +/- 203.91 pg ml-1, respectively. Corpora lutea collected from wild muskoxen between 45 and 80 days gestation all showed histological evidence of regression, while corpora lutea from mid-gestation (112-125 days) were in advanced stages of involution. Repeated ovarian ultrasonography of captive muskoxen during the first 100 days of pregnancy confirmed these findings. The unusual, early regression of the corpus luteum of pregnancy indicates that progesterone and oestrogen of mid- and late pregnancy are probably of placental origin.(ABSTRACT TRUNCATED AT 250 WORDS)

Odor of the muskox : A preliminary investigation.

The behavior of captive male muskoxen was observed closely during their characteristic superiority display, the anatomy of the preputial region was studied in two adults and three calves, and preputial washings and preorbital gland secretion were subjected to gas chromatography and mass spectroscopy. During the superiority display, the prepuce was everted to form a pendulous tube tipped with a fringe of matted hair. Owing to the movement of the animal, the urine that dribbled from the preputial opening was liberally applied to the long guard hairs of the belly. The superiority display was almost exclusively confined to dominant males and apparently accounted for their odor. In the quiescent state, the hair seen around the preputial opening was drawn inside and formed an 8 cm-wide band on the lining of the prepuce. The preputial washings contained large amounts of benzoic acid andp-cresol. The infraorbital gland secretion contained cholesterol, benzaldehyde, and a homologous series of saturated γ-lactones ranging from 8 to 12 carbons. The latter compounds and the natural secretion smell similar to the human nose.

Progesterone, oestradiol-17 beta and LH during the oestrous cycle of muskoxen (Ovibos moschatus).

Progesterone, oestradiol-17 beta and LH were measured in plasma from 6 non-pregnant, captive, female muskoxen during the 1984 and 1985 breeding seasons. Jugular blood samples were taken on an alternating 3/4-day schedule in 1984 and daily or at 4-h intervals over oestrus, via indwelling jugular cannulae, for 6 weeks in 1985. Oestrous cycle length was 19.6 +/- 0.96 (s.d.) days (n = 19) and did not vary between the first and subsequent cycles of the season. Progesterone was lowest at oestrus (less than or equal to 0.1 ng/ml), began to rise on Days 4-5, peaked on Days 10-12 (mean = 2.6 ng/ml) and returned to baseline 2-5 days before the next oestrus. A small rise in progesterone before the first cycle of the breeding season was observed on 7 of 12 occasions. Oestradiol-17 beta was significantly higher (P less than 0.001) 1-4 days before, or coincident with, oestrus. The average duration of the LH peak was 24.6 h (n = 7) and coincided with observations of behavioural oestrus. In one animal behavioural oestrus and an LH peak preceded a small progesterone rise at the beginning of the breeding season. The temporal relationship of these three hormones during the muskox oestrous cycle is very similar to that seen in domestic ruminants.