Browsing by Author "G. Archunan"

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Bromocriptine-induced implantation failure in mice: Failure of the stud male to protect pregnancy
(1992) G. Archunan; C.J. Dominic
[No abstract available]
Nutritional stress-induced implantation failure in laboratory mice: inhibition by continuous illumination.
(1995) G. Archunan; C.J. Dominic
The implantation failure in newly inseminated mice induced by food deprivation for 48 hr, beginning at 0900 hrs on day 4 post coitum, was prevented by simultaneous exposure to light continuously for 48 or 36 hr. Food-deprived females that were exposed to continuous light for 36 hr showed a significant increase in fetal resorption as compared with food-deprived females exposed to continuous light for 48 hr. Since failure of hypophysial prolactin release appears to be the primary endocrine cause of the inanition-induced implantation failure, the results suggest that exposure to continuous light protects implantation in food-deprived females by stimulating luteotrophic activity.
Nutritional Stress-Induced Implantation Failure in Newly Inseminated Mice: Effect of the Presence of Stud Males
(1989) G. Archunan; C.J. Dominic
Implantation failure was induced in a large proportion of newly inseminated female mice by food deprivation for 48 hrs beginning at 10.00 hr on day 4 post coitum. The presence of the stud male prevented implantation failure in food-deprived females. The protective effect on implantation in food-deprived females was not provided by the presence of a conspecific strange male. It is suggested that the newly inseminated female retains the olfactory “memory” of the stud male over a period of time after mating and this memory induces a luteotrophic effect in food-deprived females leading to the protection of implantation. The results also lend strong support to the view that the newly inseminated female mouse identifies her coital partner as an individual through olfactory cues. © 1989, J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart, New York. All rights reserved.
Oestrous cycle disruption in group-housed mice: evaluation of the involvement of tactile and pheromonal stimuli.
(1991) G. Archunan; C.J. Dominic
The role of tactile stimuli and pheromonal stimuli in the induction of oestrous cycle irregularities in mice was evaluated. In contrast to an adult regularly cycling female (the test female) housed in contact with 6 adult females, a test female housed in contact with 6 impuberal females failed to show disruption of oestrous cycle. Likewise, a test female housed in contact with bedding soiled by 6 group-housed adult females failed to exhibit disruption of oestrous cycle. By contrast, a test female housed in contact with 6 impuberal females on bedding soiled by 6 adult group-housed females exhibited a significant increase in the incidence of prolonged cycles. However, a test female housed with 6 impuberal females without direct contact with the bedding soiled by adult group-housed females exhibited a significant decrease in the incidence of prolonged cycles. The results suggest that tactile stimuli and pheromonal stimuli (probably present in the excrete of adult females) act synergistically in inducing cycle disruption. The findings further indicate that the female-originating pheromone involved in oestrous cycle disruption is non-volatile (not air-borne) and that it acts through contact.
Protective effect of ectopic pituitary graft on nutritional stress-induced implantation failure in mice.
(1991) G. Archunan; C.J. Dominic
Implantation failure in newly inseminated mice induced by food deprivation was prevented by the presence of an ectopic pituitary graft. Since a pituitary graft in an ectopic site is known to secrete prolactin continuously, it is suggested that suppression of implantation failure in pituitary-grafted females is due to the luteotrophic support provided by the graft. The results provide supportive evidence for the view that depression of hypophysial prolactin is the primary endocrine cause of the nutritional stress-induced implantation failure in mice.
Stud Male Protection of Implantation in Food-deprived Mice: Evaluation of the Involvement of Olfactory-vomeronasal Systems
(1990) G. Archunan; C.J. Dominic
The protection of implantation in food-deprived females provided by exposure to the stud males was not abolished following surgical ablation of the vomeronasal organ (VNO) from females. By contrast, stud males failed to protect implantation in food-deprived females made peripherally anosmic by intranasal irrigation with ZnSO4. The results suggest that the main olfactory system, and not the accessory olfactory system, is involved in the perception of the stud male-originating olfactory cue that protects implantation in nutritionally-stressed females. The findings also provide circumstantial evidence that the stud male-originating olfactory cue involved in the protective effect is volatile (air-borne). © 1990, J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart, New York. All rights reserved.
Stud male-induced protection of implantation in food-deprived mice: masking effect of an artificial scent on pheromonal odour.
(1990) G. Archunan; C.J. Dominic
In contrast to unscented stud males, stud males anointed with a commercial perfume failed to protect implantation in food-deprived females. It is suggested that the failure of perfumed stud males to protect pregnancy in their coital partners is due to the masking effect of the perfume on the stud male-originating olfactory cue which stimulates luteotrophic activity in females. The results are also consistent with the view that the newly inseminated female mouse identifies the stud male as an individual through a pheromonal cue and this is involved in the protective effect on implantation in the food-deprived female.