STUDIES ON THE MECHANISM OF NIDATION. XVI.

1965 ◽  
Vol 49 (2) ◽  
pp. 299-304 ◽  
Author(s):  
P. F. Kraicer ◽  
M. C. Shelesnyak

ABSTRACT One mg of ergocornine methanesulphate was injected into pseudopregnant rats; the time at which the vaginal smear became pro-oestrous was noted. Pro-oestrus appeared two days after the injection of ergocornine, independent of whether the drug was administered on days L1, L2, L3, L4 or L5 (L1 = first day of leucocytic vaginal smear). Injection of 5 mg/d progesterone delayed, but did not usually prevent, the onset of pro-oestrus. Pro-oestrus appeared 3 days after the last injection of progesterone. These results show that ergocornine induces the appearance of oestrus by effecting progesterone withdrawal rather than by direct activation of folliculotrophins.

Author(s):  
T. M. Crisp ◽  
F.R. Denys

The purpose of this paper is to present observations on the fine structure of rat granulosa cell cultures grown in the presence of an adenohypophyseal explant and to correlate the morphology of these cells with progestin secretion. Twenty-six day old immature female rats were given a single injection of 5 IU pregnant mares serum gonadotropin (PMS) in order to obtain ovaries with large vesicular follicles. At 66 hrs. post-PMS administration (estrus indicated by vaginal smear cytology), the ovaries were removed and placed in a petri dish containing medium 199 and 100 U penicillin/streptomycin (P/S)/ml. Under a 20X magnification dissecting microscope, some 5-8 vesicular follicles/ovary were punctured and the granulosa cells were expressed into the surrounding medium. The cells were transferred to centrifuge tubes and spun down at 1000 rpm for 5 mins.


1961 ◽  
Vol 36 (2) ◽  
pp. 180-184 ◽  
Author(s):  
Béla Flerkó ◽  
Vera Bárdos

ABSTRACT Absence of compensatory ovarian hypertrophy in »constant oestrus rats« from lesions in the anterior hypothalamic area suggests that nervous elements localized in this region play an essential role in the stimulation of gonadotrophin output by diminution of the blood oestrogen level. The constant vaginal oestrus after unilateral ovariectomy in the majority of animals was, however, repeatedly interrupted by vaginal smears of a dioestrous type. The appearance of a dioestrous vaginal smear in the »hypothalamic constant oestrus rats« is often associated with some luteinisation. It is assumed that diminution of the blood oestrogen level by reduction of ovarian tissue in these animals may bring about a release of LH sufficient to cause formation of corpora lutea.


Sign in / Sign up

Export Citation Format

Share Document