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C. M. Oldham, D. T. Pearce, and S. J. Gray

Summary. Increasing doses of progesterone from 0 to 20 mg, given as a single i.m. injection, increased the proportion of corpora lutea that had a normal life-span when induced in ewes by the introduction of testosterone-treated wethers from 54% (19/35) to 100% (34/34). Injection of progesterone did not affect the induction of ovulation and 95% (130/136) of the anovulatory ewes ovulated. Nevertheless, a low proportion of ewes displayed oestrus between Days 16 and 26 after the introduction of testosterone-treated wethers (Exp. 1, 47%, 92/196; Exp. 2, 50%, 502/1000). Many of the ewes that did not display oestrus also failed to ovulate again (Exp. 1, 70%, 37/53). The proportions of anovulatory adult and maiden ewes that ovulated after the introduction of testosterone-treated wethers were not significantly different but significantly fewer maiden ewes were detected in oestrus.

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G. D. Gray, H. N. Davis, A. McM. Kenney, and D. A. Dewsbury

Department of Physiology, Stanford University, Stanford, California 94305, and * Department of Psychology, University of Florida, Gainsville, Florida 32611, U.S.A.

The effects of mating and other stimuli on ovulation have been reported for montane voles, Microtus montanus (Cross, 1972; Gray, Davis, Zerylnick & Dewsbury, 1974; Davis, Gray, Zerylnick & Dewsbury, 1974). These voles are induced ovulators, but no data are available on the precise hormonal changes involved. In the present study, plasma levels of LH and progesterone were measured in montane voles during various reproductive states.

All voles were laboratory bred and were 4-6 months of age. They were housed individually as adults in plastic tub cages (29 × 19 × 13 cm), with San-i-cel (Paxton Processing Co., Paxton, Illinois) and Nestlets (Ancare Corp., Manhasset, New York) provided for bedding. Purina Rabbit Chow (Ralston Purina Co., St Louis, Missouri) and water were available at all times, and fresh lettuce was provided

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G. D. GRAY, H. N. DAVIS, M. ZERYLNICK, and D. A. DEWSBURY

Summary.

An investigation of the reproductive cycle of montane voles, Microtus montanus, in the laboratory gave three main findings. Firstly, this species showed a pattern of induced ovulation. Mated, oestrous females showed 100% ovulation while only two of twelve unmated, oestrous females ovulated. Secondly, there was an absence of regular oestrous cycles both when females were isolated or adjacent to males. Thirdly, there was evidence for the occurrence of a postpartum oestrous period during which fertile matings were possible. These results support the suggestion that induced ovulation and the absence of regular oestrous cycles may be characteristic of the reproductive biology of Microtus.

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R. J. Wordinger, A. E. Moss, T. Lockard, D. Gray, I-F. C. Chang, and T. L. Jackson

Summary. Uterine samples were either rapidly frozen in liquid nitrogen or placed in Bouin's fixative. A commercial primary polyclonal antibody made in rabbits against human recombinant basic fibroblast growth factor (bFGF) was used. Western blot analysis indicated that the antibody was specific for bFGF and did not react with acidic FGF. The primary antibody was followed by either goat anti-rabbit immunoglobulin G (IgG) conjugated to the fluorescent phycobiliprotein tracer phycoerythrin or biotinylated goat anti-rabbit IgG and a biotin–avidin–peroxidase complex. Specificity controls using adjacent sections were carried out by (i) substituting normal rabbit sera for the primary antisera, (ii) omitting the primary antisera or (iii) extracting sections with NaCl (2 mol l−1) prior to the immunochemical procedures. No binding of the antibody was observed with any of the specificity control sections. The connective tissue stroma and the basal lamina associated with uterine glandular and surface epithelial layers were positive for bFGF. Localization was not observed within surface or glandular epithelial cells. The basal lamina and endothelial cells associated with blood vessels within the uterus and the smooth muscle cells of the myometrium were positive for bFGF. There were no differences in uterine localization patterns or intensity during the oestrous cycle or after ovariectomy and steroid hormone supplementation. These studies demonstrate the specific localization of bFGF within the mouse uterus.

Keywords: basic fibroblast growth factor; mouse