Impact of aggressive encounters on reproductive behaviour in the Indian desert gerbil,Meriones hurrianae (Jerdon)

The gerbils were exposed to daily I min aggressive encounters for 30 days, to study the effect of social stress on reproduction. The encounters were induced by introduction of an adult male or female gerbil into the cage of a male retired breeder living in isolation. In the male gerbils the encounters decreased (P < 0.001) gonadal weight and sperm counts. The accessory sex organs responded variedly to the encounters. The surface areas of abdominal scent glands decreased (P < 0.001). The results suggest that exposure to aggressive encounters had a negative influence on male reproduction in the gerbil. Contrary to the results in male gerbils, encounters with males had a positive influence on reproduction in females. This was evidenced by data on ovarian and uterine weights, follicular kinetics and the estrous cycle. The ovarian and uterine weights increased (P < 0.001) in gerbils exposed to the encounters. The number of estruses increased (P < 0.001) whereas the diestruses decreased. Study of follicular kinetics revealed an increase in the number of growing follicles and a decrease in the number of regressive follicles. The mechanism(s) by which the encounters influence reproduction is not known. Adrenal gland weights increased (P < 0.001) in both male and female gerbils exposed to the encounters. The pinealocyte cell and nuclear diameters decreased (P < 0.01) in males and increased (P < 0.001) in female gerbils after the encounters. Presumably the adrenal and pineal glands may play an important role mediating the effects of the encounters.     

Effects of chemical occlusion of vas deferens on the reproductive organs in gerbil Meriones hurrianae Jerdon.

Male gerbils were sterilized by giving a single injection of a sclerosing chemicial (5% KMnOH) directly into the vasa. After 3 weeks the gerbils were killed. Testes, accessory sex organs, and thyroid and adrenal glands were removed and weighed. Halves of testis and epididymides were fixed in Bouin's fluid fo r microscopic study. The remaining halves were frozen and total RNA, protein, sialic acid, seminal vasicular fructose, and testicular lipids were later determined. Cholesterol estimations were also made. 2 weeks following vas injections animals were tested by exposing them to cycling estrous females. 21 days later the females were examined for possible implantation sites. It was shown that the males had been sterile. Weights of testicles, accessory sex organs, thyroid and adrenal gland remained normal, except that there was a significant increase in the weight of the ventral prostate. No histological changes were found in the testes. Protein content of the testes, epididymides, and seminal vesicles did not change. A decrease in RNA was noted. Sialic acid levels did not alter. Cholesterol and total lipids were normal. Alkaline phosphatase activity in the testes and epididymides had not changed after 3 weeks. Vasicular fructose was normal. Complete occlusion of the vasa resulted. After 100 days there was no return to fertility. The results appear to be permanent.     

Behavioural responses of desert gerbil, Meriones hurrianae after removal of scent marking gland

The desert gerbil, M. hurrianae scent marks the general substratum in its territory with the sebum exudation of mid abdominal gland and urine. Having assessed number of functions, which scent marking plays in the social life of these rodents, the scent marking behaviour was studied in animals, in which the gland was surgically removed and was compared with that of intact rodents. After recovery from the operation, the scent marking frequency of both male and female M. hurrianae declined significantly and was maintained at a low level. Surprisingly, scent marking with urine also declined considerable with time. After 5 months of the operation, desert gerbils were given a choice to respond to male and female sebum odours. The frequency of their scent marking with either sebum or urine did not show any significant enhancement as compared to their initial marking rate. However, the duration of their stay and scent marking frequency near the source of the sebum odour was more that in the clean side of the cage. The role of such altering behaviors of M. hurrianae and their impact on social organization are discussed.     

Effects of methallibure (I.C.I. 33828) on the female reproductive tract of the Indian Desert gerbil (Meriones hurrianae Jerdon).

Effects of methallibure (I.C.I. 33828) have been studied on the reproductive organs of female gerbils, Meriones hurrianae. Methallibure administration caused reduction of gonadal weight indicating suppression of pituitary gonadotrophins. In the ovaries of the treated females extensive atresia of follicles and of corpora lutea was observed. In addition methallibure interrupted the sex cycle, and a dioestrous vaginal pattern was retained throughout medication. A significant decrease in the level of RNA, protein and sialic acid in the uterus and vagina and of glycogen in the uterus was found. Histological and biochemical changes in the ovaries and uteri suggest a possible direct antioestrogenic action of the compound.     

The effect of ligation of cauda epididymidis and vasectomy on testicular function in the adult gerbil (Meriones hurrianae).

1. The effects of ligation of caput, cauda epididymides and vasectomy were studied in adult gerbils. 2. The operations were performed unilaterally, the testis and epididymides on the contralateral side serving as controls. 3. Ligation of cauda epididymides decrease testicular weight, whereas caput ligation did not change the testis weight. Accessory sex glands were reduced in size. 4. Ligation caused a drastic degeneration of the spermatogenic cells. There was a complete disruption of testicular function. Leydig cell hypertrophy was conspicuous. Caput and cauda ligation led to degenerative changes in the epididymides. Epididymal epithelium was regressed and the lumen was devoid of spermatozoa. 5. Caput and cauda ligation inhibited the synthesis of RNA, protein and sialic acid in testis and epididymides and depleted the fructose concentration in the seminal vesicle. 6. Vasectomy did not cause any alteration in sperm production during the 8 week period on the lighted side. The cytology and the biochemistry of the testis and epididymides appeared to be normal.     

Histochemical demonstration of certain testicular enzymes of the Indian desert gerbil Meriones hurrianae jerdon and their response to unilateral cryptorchidism

Summary Active male gerbils were rendered unilaterally cryptorchid and the enzymatic changes were studied after 48, 60 and 100 days. The histochemical observations revealed inhibition of alkaline phosphatase, acid phosphatase, 5-nucleotidase, adenosine-tri-phosphatase and succinic dehydrogenase activities in the germinal elements of the seminiferous tubules. The non-specific esterase and succinic dehydrogenase activities increased in the Leydig cells to certain extent. The sudanophilic lipids increased in the Sertoli cells and the interstitial cells. An attempt has been made to approach the intricate problem of the spermatogenesis in order to understand the sequence of certain enzymatic activities in the gerbil testis in which spermatogenesis is suppressed when one of the testes is lodged inside the abdominal cavity.