OESTROGENIC AND ANTIOESTROGENIC ACTIVITIES OF A NUMBER OF STEROIDS IN BEHAVIOURAL OESTRUS AND VAGINAL SMEAR ASSAYS IN THE EWE

1969 ◽  
Vol 45 (4) ◽  
pp. 549-555 ◽  
Author(s):  
D. R. LINDSAY ◽  
R. J. SCARAMUZZI

SUMMARY Fourteen synthetic steroids and androstenedione were examined in ovariectomized ewes for oestrogenic activity when administered alone and with oestradiol benzoate by intramuscular injection. None of the compounds investigated was active when administered alone, as assessed by the vaginal smear assay, and only androstenedione produced a behavioural response. Androstenedione had a MED of 8·8 mg. but was less active when administered intravenously. Several steroids acted as anti-oestrogens when injected with oestradiol benzoate. Eight steroids inhibited the behavioural response and four the vaginal response. An additive response was found with androstenedione for behavioural response and with 17β-ethyl-17-hydroxy-19-nor-4-androsten-3-one (SC-5914) for vaginal response. Vaginal and behavioural responses were not necessarily related, and responses obtained in the ewe to particular steroids were not identical with those obtained in laboratory animals by other workers using similar tests.

1969 ◽  
Vol 45 (1) ◽  
pp. 99-109 ◽  
Author(s):  
M. J. CARRICK ◽  
J. N. SHELTON

SUMMARY Experiments were conducted to examine the behavioural response of spayed heifers to oestrogen, and its modification by progesterone. In two groups of heifers, the median effective doses (MED) of oestradiol benzoate (ODB) were 121 and 132 μg. Repeated doses of ODB at physiological levels did not induce a state of refractoriness; in this respect the heifer is dissimilar to the ewe. However, repeated doses of 10 mg. ODB induced refractoriness to 400 μg. ODB. When such refractory heifers were treated with 10 mg. progesterone/day for 5 days, they showed a normal response to 400 μg. ODB given 3 days later. This return to normal sensitivity was not sustained, and pretreatment with progesterone was necessary for a normal response to subsequent small doses of ODB. The transient removal of the refractory state appears not to be due to a simple synergistic effect of residual progesterone, but to an effect of preconditioning a neural centre to respond to oestrogen. Increasing the duration of pretreatment with progesterone beyond 5 days did not result in a greater sensitivity to ODB. Pretreatment with progesterone in heifers not made refractory to ODB did not result in an increased sensitivity to ODB. Moreover, up to 7 days after termination of the progesterone treatment, the response to ODB was reduced and the slope of the dose-response line was less steep than when ODB was injected alone. The reduction of the response was more pronounced with 40 mg. progesterone/day than with 10 mg. The possible significance of these results in intact animals is discussed.


1977 ◽  
Vol 74 (3) ◽  
pp. 477-485 ◽  
Author(s):  
P. SÖDERSTEN ◽  
S. HANSEN

SUMMARY Intact 4-day cyclic rats showed sexual receptivity 24 h after an injection of oestradiol benzoate (OB) on any day of the cycle except on the second day after the display of spontaneous oestrus. Ovariectomy at the time of OB treatment abolished the behavioural response, but receptivity was restored by progesterone. Progesterone treatment early on the day of behavioural oestrus advanced the display of receptivity but did not affect the time at which oestrus ended. Repeated treatment of sexually receptive rats with progesterone did not affect the duration of oestrus. These results show that sexual receptivity in the intact rat cannot occur in the absence of oestradiol and progesterone. The results further suggest that progesterone may not be associated with the mechanisms terminating behavioural oestrus in rats. Treatment with OB on the day of oestrus can prolong the duration of receptivity but only at a higher dosage than that needed for induction of receptivity.


2021 ◽  
Author(s):  
Emily E. Denief ◽  
Julie W. Turner ◽  
Christina M. Prokopenko ◽  
Alec L. Robitaille ◽  
Eric Vander Wal

AbstractThe Anthropocene marks great changes to environments and the animals that inhabit them. Changes, such as disturbance, can affect the manner in which animals interact with their environments, such as moving and selecting habitats. To test how animals might respond to changing disturbance regimes, we employ an experimental approach to movement ecology. We used integrated step selection analysis (iSSA) to test the behavioural responses of individually-marked grove snails (Cepaea nemoralis) exposed to a gradient of physical disturbance in their habitat. We used a before-after control-impact (BACI) experimental design within semi-controlled mesocosms to manipulate edge and disturbance variables by altering the area of the mesocosm covered by bricks. We showed that grove snails perceive edges of enclosures and edges of bricks as risks, and responded to such risks by altering their movement. Grove snails displayed a bimodal response to risk by taking shelter in place or moving faster to be farther from the disturbance. Furthermore, individuals tended to modulate their behavioural response to the degree of risk. Our study highlights the usefulness of experimental mesocosms in movement ecology and in determining the effects of habitat alteration and human-imposed risk on movement behaviour.


1983 ◽  
Vol 36 (3) ◽  
pp. 295 ◽  
Author(s):  
NR Adams ◽  
GB Martin

The effects of oestradiol on plasma luteinizing hormone (LH) concentrations were examined in 15 ovariectomized control ewes and 15 similar ewes with permanent infertility after prolonged grazing on oestrogenic clover pasture ('clover disease'). Before treatment, the plasma concentrations of LH were similar in the control and affected ewes. After intravenous injection with 40 pg oestradiol-I 7 p during the anoestrous season, the decline in LH concentration was greater in the clover-affected ewes and the subsequent elevation above original baseline levels was smaller. After intramuscular injection with 15 or 30 pg oestradiol benzoate during the normal breeding season, fewer clover-affected ewes showed a surge of LH, and the response was both reduced and retarded. This difference between the two groups has not been observed in studies on intact ewes, and it is suggested that in intact ewes the difference is masked by a greater tonic LH activity in affected ewes. The results of the present study are consistent with the hypothesis that prolonged exposure to oestrogenic pasture has a differentiating, or 'androgenizing' effect on the adult ewe.


2002 ◽  
Vol 205 (19) ◽  
pp. 3087-3092 ◽  
Author(s):  
Bruce A. Young ◽  
Amie Aguiar

SUMMARYIn order to test the hypothesis that snakes can not only perceive airborne sounds, but also respond to them, an acoustic isolation chamber was designed and constructed to perform best within the 150-450 Hz range in which snakes perceive sound. Suspended within this acoustic chamber was a steel mesh basket designed to minimize the potential for groundborne vibrations. A synthesized tone was created out of 20 different 150 ms sounds, each separated by a 50 ms period of silence; the acoustic energy of each of the 20 sounds was concentrated between 200-400 Hz, and each sound included frequency modulation. The trial stimuli were presented to western diamondback rattlesnakes Crotalus atrox at a level 5-10 dB above their perception threshold. Four significant behavioural responses were observed upon stimulus presentation: cessation of body movements, reduction or cessation of tongue flicking, rapid jerks of the head and rattling. At least one significant behavioural response was observed in 92% of the behavioural trials. This study provides the first experimental evidence that snakes can respond behaviourally to airborne sounds.


1998 ◽  
Vol 201 (2) ◽  
pp. 169-177
Author(s):  
K D Joanidopoulos ◽  
W Marwan

The giant rotifer Asplanchna sieboldi swims by the propulsive effect of thousands of cilia arrayed in clusters around the apical field, which has several mechanosensory structures (sensilla) located at defined positions. Males and females differ in both their patterns of behaviour and their sensory receptor equipment. Unstimulated males swim straight with occasional spontaneous changes in direction until they hit an obstacle with their apical field. Depending on the direction and the strength of the mechanical interference, the animals show different behavioural responses. To analyse the effect of excitation of the apical mechanosensitive sensilla on these responses, males were held on microcapillaries, and the sensitivity of individual sensilla was assayed using micromanipulator-mediated mechanical stimulation. Stimulation of each of the four different types of sensillum triggered a specific and well-defined initial behavioural response. Individual animals behaved identically with respect to the receptor specificity of the responses. The behaviour of free-swimming males upon contact with obstacles or females is discussed on the basis of these results.


1976 ◽  
Vol 10 (2) ◽  
pp. 161-163 ◽  
Author(s):  
M. R. Gamble

Vaginal smear cyclicity was used as a physiological test to compare the response of rats to the new 'silent' fire alarm developed by the Laboratory Animals Centre with a conventional fire bell. The fire bell had a highly significant effect on the vaginal smear cyclicity whereas the rats exposed to the 'silent' fire alarm showed no significant changes from the control animals in quiet conditions.


Author(s):  
G. Molale ◽  
M. A. Antwi ◽  
J. N. Lekunze ◽  
U. Luvhengo

The purpose of this experiment was to evaluate the behavioural response of Boer goats and Tswana goats to successive handling. Boer goats and Tswana goats were subjected to aging and tail restrain during handling. Behavioural response was recorded through the vocalisation score (VS), crush score (CS), flight speed (FS), and flight time (FT) scores twice a week for eight weeks. A total of thirty six Boer goats and Tswana goats were used in this experiment. The results indicated that the Tswana goats were the most temperament (p < 0.05) and Boer goats were the calmest. Behavioural scores significantly increased throughout the experiment.


Author(s):  
Brendan S Talwar ◽  
Ian A Bouyoucos ◽  
Edward J Brooks ◽  
Jacob W Brownscombe ◽  
Cory D Suski ◽  
...  

Abstract Fishes are often caught as bycatch on longlines and subsequently discarded. The behavioural response of fishes to longline capture is poorly understood, although it may be linked to the magnitude of the physiological stress response, and, ultimately, contribute to stress-induced mortality. We used accelerometers, video cameras, and hook timers to analyse the behavioural response of 13 subtropical teleost and elasmobranch species to experimental longline capture in The Bahamas. We found that, across all species and species groups, fight intensity during a capture event was best described by a negative linear and positive quadratic response. Nurse sharks and tiger sharks had lower fight intensity values and exhibited less steepness in their quadratic response during the first 10 min of capture than other species, particularly blacktip and Caribbean reef sharks. Nurse sharks also exhibited the most consistent fight intensity during the entire capture event compared to other shark species, particularly the blacknose shark. Generally, obligate ram ventilators and mixed ventilators exhibited higher steepness in fight intensity trajectories than buccal/spiracular pumpers, which had more consistent, lower fight intensity values. Behavioural responses to longline capture are species specific but may be linked to distinct evolutionary traits such as respiratory mode.


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