Summary. Mature, non-pregnant, female armadillos (Dasypus novemcinctus) were killed throughout the year (3–6/month, N = 54) and both ovaries were examined for follicular development. All normal and atretic follicles > 358 μm were counted. Total number of normal follicles remained constant from January to June but decreased by 50% in the remaining months except in October and November. Follicles > 978 μm (those likely to be ovulated) were found during each month but more (>3/ovary) were present during April, May, June and October. Atretic follicles remained constant (4–6) except in July and August when the number (10–12) was doubled. A single CL was present in 2/4, 6/6, 1/6, 1/3 and 2/3 animals in July, August, October, November and December, respectively. These data confirm that armadillos ovulate in July and suggest that ovulation may also occur in some animals in late October or November.
R. D. PEPPLER, M. H. BENNETT and J. D. DUNN
Thirty-two prepubertal, female rats (Southern Farms) were allocated to intact control, bilateral optic enucleation (blinded), bilateral olfactory bulb removal (anosmic) and blinded—anosmic groups. Olfactory bulbs were surgically removed between 27 and 29 days of age and eyes were removed at 30 days of age. One ovary was removed from each animal between 107 and 112 days of age on Day 2 (metoestrus) of the oestrous cycle. The number of eggs ovulated was determined by flushing the oviducts with normal saline solution. All rats completed one oestrous cycle and were killed at metoestrus of the following cycle. There was no difference in the number of ova shed between the four groups at the time of removal of the first ovary. One cycle later, compensatory ovulation was found at autopsy to have occurred in all animals. Controls ovulated 10·3±0·5 eggs; blinded, 9·6±0·7; anosmic, 10·3±0·3; and blinded—anosmic, 9·7±0·8. Follicular development was quantitatively analysed in both intact and hemispayed blinded and/or anosmic rats. These data suggest that pituitary—ovarian function as evaluated by the number of eggs ovulated is not affected by blinding and/or anosmia.
H. Jane Weems Chihal, S. C. Stone and R. D. Peppler
Departments of Physiology, Anatomy, and Obstetrics and Gynecology, Louisiana State University Medical Center, New Orleans, Louisiana 70112, U.S.A.
Lipschütz (1927) suggested that the number of eggs shed by an animal is not determined by the number of ova present, but by some extra-ovarian factor. When Breward & Zuckerman (1949) attempted to test this hypothesis, they showed that multiple ovarian grafts in randomly bred female rats caused a decrease in follicular development and the weight of the ovaries in situ. These findings were later attributed to immunological rather than endocrinological factors (Mandl & Zuckerman, 1951). In the present study, the influence of `extra' ovarian tissue on the number of eggs ovulated and follicular development was re-investigated using highly inbred Fischer 344 rats. In such strains skin homografts are permanently accepted, verifying the isohistogenicity of the strain (Warren, Lofgreen & Steinmuller, 1973). Since skin grafts are more difficult to transplant permanently in
R. D. Peppler, F. E. Hossler and S. C. Stone
Summary. At 3-month intervals from birth to 27 months of age, 3 female armadillos were killed. The number and size of follicles >202 μm were determined, plasma progesterone concentration was measured, and values were correlated with age. Blood samples were taken monthly by femoral vein puncture and plasma was analysed by radioimmunoassay for progesterone concentration. At necropsy, both ovaries were visually inspected for a corpus luteum, weighed and then processed for routine histology. The number of normal, antral follicles >202 μm were counted. These follicles were arbitrarily categorized into 15 different size groups (every 77μm). Total number of follicles >202 μm varied from 15·5± 1·3 at 15 months of age to 26·3 ± 1·9 at 21 months. Follicles of a size (>978 μm) most likely to ovulate were present only at ≥9 months of age. Progesterone values remained below the adult concentration (5 ng/ml) until 15 months of age. A concentration of progesterone indicative of ovulation (∼ 10 ng/ml) occurred between 17 and 20 months of age. The findings of the present study demonstrate that the female armadillo is reproductively mature after 15 months of age.