Search Results

You are looking at 1 - 7 of 7 items for

  • Author: W. K. WHITTEN x
  • Refine by Access: All content x
Clear All Modify Search
Restricted access

W. K. WHITTEN

SUMMARY

When mouse ova were grafted under the renal capsule, the proportion of mice showing evidence of implantation was the same for normal and hypophysectomized animals.

The injection of oestradiol dipropionate into pregnant lactating mice, on the 5th day post partum, produced macroscopic evidence of uterine implantation 26 hr later. This was not seen until 28 hr after an injection of serum gonadotrophin.

The physiological significance of these findings is discussed.

Restricted access

W. K. WHITTEN

SUMMARY

1. The ovaries and uteri of mature female mice rendered anosmic by removal of the olfactory bulbs were significantly smaller than those of control animals. Corpora lutea were absent or atrophic, and the vagina was closed in most of these animals.

2. No effect on the testes of anosmic males was observed. The accessory glands were lighter and contained less secretion, but the epithelium appeared unchanged.

3. Body weights of both male and female mice were reduced.

Restricted access

W. K. WHITTEN

SUMMARY

1. The action of progesterone on the development of the mouse ovum from the eight-celled stage to the blastula has been studied in vitro.

2. Concentrations of progesterone below 2 μg/ml. produced no observable effect, whereas some toxicity was observed at 4 μg/ml. and few ova survived higher concentrations.

3. Herniation of the zona pellucida by the developing blastula is described; this process was inhibited by 4 μg/ml., but not by 2 μg/ml. of progesterone.

4. Blastulae appear to be more sensitive to the action of progesterone than are earlier stages.

5. Oestrogens afforded no demonstrable protection against the toxic action of progesterone when added to the culture medium.

6. The possible physiological significance of these findings is discussed.

Restricted access

W. K. WHITTEN

SUMMARY

When female mice were caged in groups of thirty, regular oestrous cycles did not occur in the majority of animals. The vaginal smears of these mice were mucified and some remained so for 40 days. Cycles promptly returned when the mice were caged individually.

The ovaries of the grouped mice were significantly lighter than those of individually housed controls, although the body weights were not different. Fewer of the grouped animals had tubal ova and corpora lutea were absent from, or atrophic in, some of the ovaries.

A decidual reaction was obtained in only one of ninety animals following trauma of the endometrium.

When grouped mice were subsequently paired, mating occurred 3 nights later in 53%. When females were caged singly the occurrence of mating was distributed more evenly over the first 4 nights.

Regular oestrous cycles did not occur in blind mice while they were grouped or in mice when they were separated by partitions in the cage.

It is concluded that anoestrus occurs when mice are grouped and results from a depression of pituitary gonadotrophic function. This depression is independent of mutual visual or tactile stimuli.

Restricted access

W. K. WHITTEN

SUMMARY

1. Mating of mice does not occur with equal frequency during the first 4 nights after pairing. Fewer than the expected number mate on the 1st, 2nd and 4th nights, but mating on the 3rd night greatly exceeds expectation.

2. This effect is not dependent on age or parity, and is little altered by pairing the mice at 11 p.m. when oestrous behaviour is fully established.

3. Mating occurs more frequently on the 1st night after pairing if the male has been enclosed in a small basket within the female's cage for 2 days previously. Also, the incidence of mating is altered by placing the females in a cage recently contaminated by males.

4. The oestrous cycle of the mouse is apparently modified by the presence of a male or his excreta, and an exteroceptive stimulus functioning through one of the chemical senses is probably involved.

Restricted access

W. K. WHITTEN

SUMMARY

1. It has been demonstrated in three strains of mice, one heterozygous and two inbred, that the oestrous cycle, as determined by vaginal smears, was shorter in the presence of a male than when males were absent.

2. When female mice were removed from males during metoestrus the duration of the ensuing cycle was the same as that observed in the absence of males. This indicates that the effect of stimuli received during one cycle was not carried over to the next.

3. The cycle was shortened when a male was present for the 48 hr following the start of metoestrus. When the period of exposure was reduced or postponed for 24 hr after metoestrus the shortening observed was not significant.

4. When a male was placed in a basket within the female's cage pseudopregnancy was not observed, but the incidence of abnormal cycles was reduced.

5. The duration of pseudopregnancy was not altered by the presence of a male.

Restricted access

W. K. WHITTEN

SUMMARY

1. The ovaries and uteri of non-lactating mice on the 7th day after parturition are significantly heavier and histologically more active than those of lactating mice.

2. The response to serum gonadotrophin injected on the 2nd day after parturition is of the same order in both lactating and non-lactating mice. This indicates that the ovary is not refractory to gonadotrophin during early lactation.

3. Injection of 5 or 10 i.u. serum gonadotrophin on the 3rd or 5th day after parturition results in normal implantation in lactating mice; injection after 2 days inhibits implantation in both lactating and non-lactating animals, presumably by tubal locking of ova.

4. It has been confirmed that injection of 0·03 μg oestradiol results in implantation at the normal time in lactating mice. There is, however, no indication from the weights of the ovaries of ovarian stimulation, and it is presumed that oestradiol acts directly on the blastocyst, the uterus or on both.

5. It is concluded that the delay in implantation associated with lactation in the mouse is due, at least in part, to reduced secretion of gonadotrophin by the pituitary and the consequent decrease in oestrogen production.