scholarly journals Effects of gonadotropin administration and transplantation of the pituitary gland on incidence of implantation in immature rats.

1988 ◽  
Vol 34 (1) ◽  
pp. 26-30 ◽  
Author(s):  
Isao ISHIBASHI ◽  
Tetsuro ABE ◽  
Yuichiro NISHIFUJI ◽  
Tetsuyuki SUGA
Keyword(s):  
Pituitary Gland ◽  
Immature Rats

EFFECTS OF CLOMIPHENE ON THE PHYSIOLOGY OF REPRODUCTION IN THE RAT

1964 ◽  
Vol 47 (4) ◽  
pp. 669-675 ◽  
Author(s):  
Somnath Roy ◽  
Virendra B. Mahesh ◽  
Robert B. Greenblatt
Keyword(s):  
Pituitary Gland ◽  
Induction Of Ovulation ◽  
Receptor Sites ◽  
Immature Rats

ABSTRACT The uptake of intravenously administered tritiated oestradiol by the uterus and pituitary gland of untreated, as well as clomiphene pretreated immature rats was studied to elucidate the nature of the antioestrogenic action of clomiphene. The results indicate that this agent competes with the natural oestrogen for the receptor sites in the uterus and pituitary gland and prevents the entry of oestrogen to and probably displaces it from the receptor sites. The significance of these observations with respect to the ability of clomiphene for the induction of ovulation in anovulatory women is discussed.

scholarly journals Nitric oxide sensitive-guanylyl cyclase subunit expression changes during estrous cycle in anterior pituitary glands

2009 ◽  
Vol 296 (4) ◽  
pp. E731-E737 ◽  
Author(s):  
Jimena P. Cabilla ◽  
Sonia A. Ronchetti ◽  
Silvana I. Nudler ◽  
Eliana A. Miler ◽  
Fernanda A. Quinteros ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Pituitary Gland ◽  
Estrous Cycle ◽  
Guanylyl Cyclase ◽  
Anterior Pituitary ◽  
Acute Treatment ◽  
Α Subunit ◽  
Immature Rats ◽  
Subunit Expression ◽  
Pituitary Glands

17β-Estradiol (E2) exerts inhibitory actions on the nitric oxide pathway in rat adult pituitary glands. Previously, we reported that in vivo E2 acute treatment had opposite effects on soluble guanylyl cyclase (sGC) subunits, increasing α1- and decreasing β1-subunit protein and mRNA expression and decreasing sGC activity in immature rats. Here we studied the E2 effect on sGC protein and mRNA expression in anterior pituitary gland from adult female rats to address whether the maturation of the hypothalamus-pituitary axis influences its effects and to corroborate whether these effects occur in physiological conditions such as during estrous cycle. E2 administration causes the same effect on sGC as seen in immature rats, and these effects are estrogen receptor dependent. These results suggest that E2 is the main effector of these changes. Since the sGC α-subunit increases while the sGC activity decreases, we studied if other less active isoforms of the sGC α-subunit are expressed. Here we show for the first time that sGCα2 and sGCα2 inhibitory (α2i) isoforms are expressed in this gland, but only sGCα2i mRNA increased after E2 acute treatment. Finally, to test whether E2 effects take place under a physiological condition, sGC subunit expression was monitored over estrous cycle. sGCα1, -β1, and -α2i fluctuate along estrous cycle, and these changes are directly related with E2 level fluctuations rather than to NO level variations. These findings show that E2 physiologically regulates sGC expression and highlight a novel mechanism by which E2 downregulates sGC activity in rat anterior pituitary gland.

CHANGES IN PITUITARY FSH AND LH AND PLASMA LH IN IMMATURE RATS TREATED WITH PREGNANT MARE'S SERUM

1972 ◽  
Vol 70 (2) ◽  
pp. 220-230
Author(s):  
Shao-Yao Ying ◽  
Roland K. Meyer
Keyword(s):  
Pituitary Gland ◽  
Gradual Decrease ◽  
Immature Rats

ABSTRACT The concentrations of LH and FSH in the pituitary gland and LH in the plasma from immature rats treated with saline, 3 IU, or 12 IU PMS were measured for 4 days. There was no detectable LH in 1.5 ml of plasma at any time in saline-treated rats. In 3 IU PMS rats, an elevation was observed at 3.00 p. m. and 8.00 p. m. on day 24. The plasma LH level of 12 IU PHS rats was much higher than that of 3 IU PMS rats, reaching a maximum at 10.00 a. m. on day 23, then gradually decreasing until the morning of day 25. The pituitary FSH content in 3 IU PMS rats reached a maximum at 10.00 a. m. on day 24, then drastically decreased at 3.00 p. m. and 8.00 p. m. The pituitary FSH content of 12 IU PMS rats showed a gradual decrease without an acute release on the afternoon of day 24. These results indicate that FSH, like LH, is released on the afternoon of day 24 and may be involved in ovulation. The failure of 12 IU PMS rats to ovulate is probably due to (a) interference in the timing of ovulating hormone (OH) release, (b) lack of a surge of LH, or (c) improper ratio of LH to FSH.

OVULATION IN IMMATURE RATS TREATED WITH OVINE FOLLICLE-STIMULATING HORMONE: FACILITATION BY PROGESTERONE AND INHIBITION BY CONTINUOUS LIGHT

1967 ◽  
Vol 38 (2) ◽  
pp. 187-194 ◽  
Author(s):  
R. K. MEYER ◽  
C. E. McCORMACK
Keyword(s):  
Luteinizing Hormone ◽  
Pituitary Gland ◽  
Follicle Stimulating Hormone ◽  
Subcutaneous Administration ◽  
Continuous Light ◽  
Hormone Activity ◽  
Immature Rats ◽  
Stimulating Hormone

SUMMARY Ovulation in immature rats induced by daily subcutaneous administration of sheep follicle-stimulating hormone (FSH) was prevented by appropriately timed injection of phenobarbitone or by exposure to continuous light. Progesterone produced ovulation in light-blocked rats and in rats kept in standard lighting which had received a non-ovulatory dose of FSH. These findings are interpreted to mean that ovulation produced by these preparations of FSH was due to a release of ovulating hormone from the pituitary gland. It is suggested that slight luteinizing hormone activity in an FSH preparation produces ovulation by causing the secretion of progesterone which then facilitates the release of ovulating hormone from the pituitary gland.

scholarly journals Ovarian stimulation by oestrogens: Effects in immature hypophysectomized rats

1944 ◽  
Vol 132 (867) ◽  
pp. 189-199 ◽  
Keyword(s):  
Pituitary Gland ◽  
Ovarian Stimulation ◽  
Ovarian Follicles ◽  
Daily Injection ◽  
Primordial Follicles ◽  
Adult Rat ◽  
Ovary Weight ◽  
Rapid Fall ◽  
Immature Rats ◽  
Hypophysectomized Rats

The rapid fall in ovary weight that follows hypophysectomy in immature rats may be pre­vented if a tablet of stilboestrol is implanted when the pituitary gland is removed. Under this treatment the number of ovarian follicles greater than 200 μ in diameter is significantly increased though the size of the largest follicles in the ovary is unchanged. The follicles in the treated rats are predominantly solid. These facts suggest that oestrogen stimulates the proliferation of the membrana granulosa. The atrophy of the interstitial cells of the ovary is not prevented. When the stilboestrol is implanted 17 days after hypophysectomy only the few semi-mature follicles, which are not yet atrophied, are stimulated; the primordial follicles are unaffected. Injection of an amount of antigonadotrophic serum sufficient to neutralize the gonado­trophin secreted by the pituitary of an adult rat does not interfere with the ovarian stimula­tion produced by oestrogen. The daily absorption from the stilboestrol tablets is about 120 μ g. Similar effects are produced by the daily injection of 100 μ g. of oestrone. Stimulation is histologically demonstrable with daily injections of 12.5 μ g. of oestrone. These doses are not regarded as unphysiological for reasons which are discussed.

Improved immunolabelling of ultrathin cryosections using antibody conjugated with 1nm gold particles

1990 ◽  
Vol 48 (3) ◽  
pp. 928-929
Author(s):  
Morten H. Nielsen ◽  
Lone Bastholm
Keyword(s):  
Pituitary Gland ◽  
Liquid Nitrogen ◽  
Electron Density ◽  
Small Diameter ◽  
Cytochemical Staining ◽  
Gold Particles ◽  
Labelling Density ◽  
Ultrathin Cryosections ◽  
Mouse Pituitary ◽  
Electron Microscopical

During the last 5 years the diameter of the gold probes used for immuno-cytochemical staining at the electron microscopical (EM) level has been decreased. The advantage of small diameter gold probes is an overall increased labelling density. The disadvantage is a lower detectability due to the low electron density of smaller gold particles consequently an inconvenient high primary magnification needed for EM examination. Since 1 nm gold particles are barely visible by conventional EM examination the need for enlargement by silverenhancement of the gold particles has increased.In the present study of ultrathin cryosectioned material the results of immunostaining using 5 nm gold conjugated antibody and 1 nm gold conjugated antibodies are compared after silverenhancement of the 1 nm gold particles.Slices of freshly isolated mouse pituitary gland were immersion fixed for 20 min in 2 % glutaraldehyde /2 % paraformaldehyde. Blocks cryoprotected with 2.3 M sucrose were frozen in liquid nitrogen and ultra-cryosectioned on a RMC cryoultra-microtome.

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