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  • Author: B. E. ELEFTHERIOU x
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B. E. ELEFTHERIOU and M. B. KRISTAL

Summary.

Virgin female mice of two unrelated, highly inbred strains, BALB/cBy and C57BL/6By, seven of their derived recombinant inbred strains, and their F1 hybrid generations, were exposed either to an intermittently ringing bell or to a flashing, high-intensity light. The females were treated, before exposure, with 1·5 i.u. PMSG. After exposure, the number of ova per treated or per responding female and the percentage of responding females were counted. The matching strain distribution pattern and the test of a congenic line permitted characterization of a gene exerting a major effect on bell- or flash-induced ovulation. The gene is located in Chromosome 4 (LG VIII). We propose the symbol Bfo. There appeared to be one or more additional loci involved and possibly interaction between loci.

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B. E. ELEFTHERIOU and A. J. ZOLOVICK

Summary.

Lesions were placed bilaterally in the medial and basolateral amygdaloid nuclei of adult female deermice (P. m. bairdii) by means of a Radio Frequency Lesion Maker with a current of 20 μA/30 sec. It was found that females with lesions in the basolateral amygdaloid nucleus exhibited normal cyclic vaginal smears and mating activities. However, 30% of the females exhibited hypersexuality as evaluated by excessive mating and reception of the male during dioestrus. Females with lesions in the medial amygdaloid nucleus exhibited normal oestrous cyclic activity, but did not mate during the entire 30-day period of the experiment. It is concluded that the medial amygdaloid nucleus may be involved in the nervous mechanism of normal mating.

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B. E. ELEFTHERIOU and A. J. ZOLOVICK

Summary.

Lesions were made by electrocoagulation in the basolateral amygdaloid group in female deermice, P. m. bairdii. Levels of luteinizing hormone in the plasma increased significantly and levels of lh in the pituitary decreased in animals with lesions. The plasma level of lh 3 weeks after lesioning was 31% higher than that during oestrus, at which the highest levels occur. The tentative conclusion is reached that the basolateral amygdaloid complex may, under normal conditions, exert an inhibitory effect on the pituitary secretion of lh.

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C. M. CHRISTENSON and B. E. ELEFTHERIOU

Summary.

Female C57BL/6J mice were injected on Day 24 of age with one of the following doses of pmsg: 1, 2, 4, 8, 16 or 24 i.u., and again on Day 26 with an identical dose. More than 85 % of the variation of the number of ova produced between doses 1 and 16 is accounted for by its corresponding variation in dose. At 24 i.u. of pmsg, the response declined significantly.This phenomenon indicates that pmsg, an fsh-like substance, not only provides for follicular maturation but also can cause release of ova without the synergistic effect of hcg, an lh-like substance, perhaps through stimulation of the release of endogenous lh.

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R. L. CHURCH and B. E. ELEFTHERIOU

Following development of more accurate and sensitive chemical and physical identification techniques for oestrogen determinations, many species have been studied. Since 1955 oestrogenic steroids have been identified in at least twenty-five species of animals. In our laboratory, the dog (Metzler, Eleftheriou & Fox, 1966), the channel catfish (Eleftheriou, Boehlke & Tiemeier, 1966a) and the deer (Eleftheriou, Boehlke, Zolovick & Knowlton, 1966b) have been studied.

The oestrogen picture has been notably inconsistent as to types of oestrogens produced in various species and to quantitative levels maintained in the blood, ovary and placenta. Although oestradiol-17β seems to be the major oestrogen in most of the species examined, there is no observed pattern in either oestrogen types or levels of circulating oestrogen metabolites in the blood within the animal kingdom. Studies reported here attempted to identify the oestrogens in the plasma, ovary and placenta of the laboratory guinea-pig and to quantitate these oestrogens using a fluorometric technique.

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F. H. BRONSON, B. E. ELEFTHERIOU and E. I. GARICK

Summary.

Inseminated deermice (Peromyscus maniculatus bairdii) were exposed for 24 hr to strange male or female (1) P. m. bairdii; (2) P. m. gracilis (an inter-fertile subspecies); or (3) C57BL/10J house mice (members of a different family of rodents). Implantation was significantly affected except in the case of exposure to bairdii or C57BL/10J females. Exposure to male bairdii and male gracilis caused the highest incidence of blocked pregnancies. Differences between the sexes in producing implantation failures in inseminated bairdii were marked in bairdii and negligible in gracilis and C57BL/10J mice.

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B. E. ELEFTHERIOU, C. DESJARDINS and A. J. ZOLOVICK

Summary.

Bilateral lesions were made by electrocoagulation in one of the following amygdaloid areas : basolateral, cortical or medial in adult male deermice. Animals were killed 20 days after the operation, and determinations were made of pituitary lh concentrations, hypothalamic lh-RF potencies and seminal vesicle fructose concentrations. Data indicate that lesions placed in either the basolateral or cortical amygdaloid areas, but not in the medial, result in significant increases in pituitary lh and plasma lh as interpreted by the significant increases in dry seminal vesicle weight and fructose concentrations. Hypothalamic lh-RF concentrations decline significantly in animals with medial lesions while increasing significantly in animals with basolateral or cortical amygdaloid lesions.

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M. X. ZARROW, B. E. ELEFTHERIOU and V. H. DENENBERG

Summary.

Three strains of mice (SWR/J, C57BL/6J and BALB/cJ) were examined for pheromonal facilitation of both PMSG- and HCG-induced ovulation. Immature females were injected with sufficient levels of the hormones to induce minimal egg release. Exposure to adult males involved the use of both the homologous and heterologous strains. The SWR/J and BALB/cJ females showed significant facilitation of ovulation with either gonadotrophin and exposure to adult males of the same or heterologous strain. Exposure of the three strains of females to C57BL/6J males, however, failed to result in any facilitation; but exposure of the C57BL/6J females to males of the SWR/J and BALB/cJ strains did result in facilitation. It may be concluded that the failure of pheromonal facilitation in the C57BL/6J strain is due to an inability of the males of this strain to produce the pheromone. The C57BL/6J females, however, still possess the ability to respond and, consequently, have not lost the receptors for the pheromone.

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B. E. ELEFTHERIOU, D. W. BAILEY and M. X. ZARROW

During the course of studies on pmsg- and hcg-induced pheromonal facilitation of ovulation (Zarrow, Christenson & Eleftheriou, 1971; Zarrow, Eleftheriou & Denenberg, 1972), strain differences were noted in the response of the immature female mouse to both pmsg and hcg. Since strain differences have been reported previously for pheromonal block of pregnancy (Bruce, 1968), and it was postulated that this system existed as a single gene (Chapman & Whitten, 1968), the following experiments were conducted to determine the heritability of the male pheromonal system involved in pmsg-induced facilitation of ovulation.

Female mice of the C57BL/6J and SWR/J strains were housed, one per cage, following weaning at 21 days of age. Lighting was kept on a 12 hr on/12 hr