ULTRASTRUCTURE AND IMMUNOCYTOCHEMISTRY OF THE PARS DISTALIS OF THE FEMALE RAT WHEN GRAFTED UNDER THE KIDNEY CAPSULE AND A PARALLEL STUDY OF THE PLASMA LEVELS OF PROLACTIN

1981 ◽  
Vol 89 (1) ◽  
pp. 157-NP ◽  
Author(s):  
L. I. AGUADO ◽  
G. S. ALVIAL ◽  
E. M. RODRÍGUEZ
Keyword(s):  
Light And Electron Microscopy ◽  
Secretory Activity ◽  
Ultrastructural Level ◽  
Lymphoid Cells ◽  
Female Rats ◽  
Secretory Cells ◽  
Female Rat ◽  
Plasma Prolactin ◽  
Kidney Capsule ◽  
Hormone Content

Two hypophysial partes distales were grafted under the kidney capsule of intact female rats. The plasma prolactin levels 15, 45 and 90 days after the operation were determined. At the same postoperative intervals the grafted glands of some of the operated rats were processed for conventional light and electron microscopy and for the demonstration of prolactin, FSH and LH according to the unlabelled immunoperoxidase procedure. The ultrastructural characteristics of the transplanted secretory cells and the amount and distribution of the immunoreactive material within their cytoplasm were used to evaluate approximately the secretory activity of these cells. Although levels of prolactin in the three experimental groups were significantly higher than those in control rats, a decrease in prolactin level was detected in 71% of the samples taken 45 days after operation. At day 15 the graft was completely surrounded by lymphoid cells whereas at day 45 these cells had invaded the whole graft. In the group sampled at day 90 the graft was free of lymphoid cells. When traced immunocytochemically the three types of cells followed different patterns of evolution after transplantation. Most prolactotrophs were hypertrophied in all groups but, in addition, they underwent a process leading to hyperplasia some time between days 45 and 90 after operation. Syncytial formations which probably correspond to multinucleated prolactotrophs were present only in the group sampled at day 90. The number of LH and FSH cells had decreased in the group at day 45 and by day 90 the former remained scarce but immunoreactive FSH cells were no longer found. At the ultrastructural level clear signs of involution of gonadotrophs and degradation by macrophages were seen in the graft 45 days after operation. The relation between the morphology and hormone content of the graft and hormone content of the plasma is discussed, together with several questions raised by the results. Pituitary transplantation can be used as an experimental model only if the time-dependent changes described here are taken into account.

PROLACTIN STIMULATION TEST WITH PERPHENAZINE: AN EVALUATION OF PLASMA PROLACTIN LEVELS AND PITUITARY SECRETORY ACTIVITY IN THE RAT

1976 ◽  
Vol 68 (3) ◽  
pp. 355-368 ◽  
Author(s):  
A. A. VAN DER GUGTEN ◽  
P. C. SAHULEKA ◽  
G. H. VAN GALEN ◽  
H. G. KWA
Keyword(s):  
Adult Male ◽  
Secretory Activity ◽  
Female Rats ◽  
Male Rats ◽  
Plasma Prolactin ◽  
Prolactin Release ◽  
Oestrogen Treatment ◽  
Endocrine Status ◽  
Pituitary Prolactin ◽  
Single Plasma

SUMMARY Many investigations of the regulation of prolactin synthesis and release are based on single plasma prolactin determinations. The purpose of the present experiment was to ascertain whether groups of rats (i.e. young or adult, male or female animals, being either intact, gonadectomized or gonadectomized and treated with oestrone), differing in age and/or endocrine status, will react to a single dose of perphenazine by an acute release of pituitary prolactin in proportion to their initial plasma prolactin levels. No consistent relation existed between the classification of the twelve groups of rats into three categories of basal plasma prolactin levels (i.e. < 20, 25–50, > 125 ng/ml) and their response to perphenazine. Even though all groups showed a highly significant increase of plasma prolactin levels the magnitude of the maximum prolactin response at 30 min varied greatly within the groups of one category and thus was not related to the initial prolactin levels. The effect of 14 days of oestrone treatment in increasing plasma prolactin levels in gonadectomized animals was greatest in young and adult male rats, less in young females and not significant in adult females. The results obtained after perphenazine treatment in the latter group made it clear that the effect of oestrogen treatment on prolactin release can be completely blocked by increasing synthesis and/or release of the prolactin-release inhibiting factor (PIF). Since perphenazine induces decrease of pituitary prolactin and a concomitant increase of plasma prolactin levels through lowered PIF-action, the positive effect of oestrogens on prolactin release (as observed in gonadectomized male and young female rats) apparently is caused by a different mode of action. The implications of these findings for the regulation of prolactin release, as affected by the endocrine status of the rat, is discussed. Moreover, comparison of prolactin lost from the pituitary and gained in the circulation of the experimental animals, with amounts of prolactin that were observed to disappear from plasma during the experiment, provided suggestive evidence that the capacity to synthesize and/or eliminate prolactin, after a sudden provoked release of the hormone, differed among the groups. The rates of synthesis by the pituitary, of release from the pituitary into the circulation as well as of elimination of the hormone from the circulation (equally involved in determining actual plasma levels) are thought, therefore, to be far more important for the elucidation of prolactin regulation than single plasma prolactin determinations.

scholarly journals Immunohistomorphometric Features of ACTH Cells in Juvenile Rats after Treatment with Estradiol or Human Chorionic Gonadotropin

2012 ◽  
Vol 31 (1) ◽  
pp. 34-39 ◽  
Author(s):  
Verica Milošević ◽  
Danijela Todorović ◽  
Miroslava Veličković ◽  
Nataša Ristić ◽  
Gordana Ušćebrka ◽  
...  
Keyword(s):  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Neonatal Period ◽  
Secretory Activity ◽  
Treated Group ◽  
Inhibitory Effect ◽  
Volume Density ◽  
Female Rats ◽  
Female Rat ◽  
Juvenile Rats

Immunohistomorphometric Features of ACTH Cells in Juvenile Rats after Treatment with Estradiol or Human Chorionic GonadotropinEstradiol and human chorionic gonadotropin (hCG) are very important in controlling the secretory activity of hormone producing cells in the female rat pituitary glands. The aim of the present study was to examine the morphometric parameters of immunohistochemically labeled ACTH cells in juvenile (16th day) female rat pituitaries after treatment with five doses of estradiol dipropionate (EDP) and two doses of hCG during the neonatal period of life. The controls were treated on the same schedule with an equivalent volume of vehicle. All animals were sacrificed 24 h after the last treatment. ACTH-producing cells were studied using the peroxidase-antiperoxidase immunohistochemical procedure. The absolute and relative pituitary weights were increased (p<0.05) only in the EDP treated group by 120.0% and by 121.1% respectively, in comparison with the controls. In this group, the volume of ACTH cells, volume of their nuclei and volume density were significantly decreased (p<0.05) by 6.4%, 33.3% and 46.2% respectively, compared to the corresponding controls. After treatment with hCG, there were no significant (p>0.05) changes neither in the volume of ACTH cells nor in the volume of their nuclei, in comparison with the controls. On the basis of the results obtained in our study, it can be concluded that EDP, injected into female rats during the neonatal period of life, has an inhibitory effect on the immunohistomorphometric parameters of ACTH cells, but such an effect is not clearly expressed after treatment with hCG.

scholarly journals Effect of taxol on secretory cells: functional, morphological, and electrophysiological correlates.

1985 ◽  
Vol 100 (6) ◽  
pp. 1863-1874 ◽  
Author(s):  
J Thuret-Carnahan ◽  
J L Bossu ◽  
A Feltz ◽  
K Langley ◽  
D Aunis
Keyword(s):  
Chromaffin Cells ◽  
Secretory Activity ◽  
Ultrastructural Level ◽  
Secretory Cells ◽  
Patch Clamp Technique ◽  
Cell Axis ◽  
Ultrastructural Studies ◽  
Microtubule Polymerization ◽  
Long Term Effect

The effect of 0.5-1.0 microM taxol, a potent promoter of microtubule polymerization in vitro, was studied on the secretory activity of chromaffin cells of the adrenal medulla. Taxol was found to have a dual effect: the long-term effect (after a 1-h incubation) of taxol was to induce almost complete inhibition of catecholamine release, whereas after a short incubation (10 min) a massive, nicotine-independent release of catecholamine was produced. From results obtained using the patch-clamp technique to study the Ca++-dependent K+ channels (Ic channels), it was possible to conclude that taxol probably provokes an augmentation of free [Ca++]i in the cytoplasm, values increasing from 10(-8) M at rest to several 10(-7) M. The increased spontaneous release of stored neurohormones and the increased frequency of opening of Ic channels occur simultaneously and could both originate from a rise of [Ca++]i upon taxol addition. Immunofluorescence and ultrastructural studies showed that 13-h taxol treatment of chromaffin cells led to a different distribution of secretory organelles, and also to microtubule reorganization. In treated cells, microtubules were found to form bundles beneath the cell membrane and, at the ultrastructural level, to be packed along the cell axis. It is concluded that in addition to its action on microtubules, the antitumor drug taxol has side effects on the cell secretory activity, one of them being to modify free [Ca++]i.

OXYDATION DES ANABOLIKUMS 1-METHYL-ANDROST-1-EN-17β-OL-3-ON MIT WASSERSTOFFTRANSFER AUF ÖSTRON

1971 ◽  
Vol 67 (3) ◽  
pp. 517-530 ◽  
Author(s):  
Martin Wenzel
Keyword(s):  
Rat Liver ◽  
Anabolic Steroid ◽  
Female Rats ◽  
Male Rats ◽  
Female Rat ◽  
Liver Slices ◽  
Androgen Effects ◽  
Biochemical Difference

ABSTRACT With the aid of metenolon-17α-T a tritium-transfer to oestrone in rat liver slices was demonstrated. This tritium-transfer from metenolon17α-T to oestrone yielding tritium-labelled oestradiol had a higher efficiency in male than in female rat liver. Correspondingly in the presence of metenolon the relation of oestrone to oestradiol is changed more in male than in female rat liver. Looking for biochemical differences between the anabolic steroid metenolon and testosterone the oxydation at C17 was measured in different organs of the rat using 17α-T-labelled steroids. The highest oxydation rate was found for both steroids in the liver. In the sexual organs of male rats the oxydation rate of testosterone was 50–10 times higher than that of the anabolic steroid. This difference was less in sexual organs of female rats. This result of a greater biochemical difference between both steroids in males than in females leads to the question, whether the dissociation between the anabolic and the androgen effects is higher in males than in females.

GONADOTROPHIN PATTERNS IN MALE AND FEMALE RATS:

1968 ◽  
Vol 58 (4) ◽  
pp. 600-612 ◽  
Author(s):  
Robert Boyd ◽  
Donald C. Johnson
Keyword(s):  
Ascorbic Acid ◽  
Testosterone Propionate ◽  
Female Rats ◽  
Female Rat ◽  
Feedback Effects ◽  
Male And Female ◽  
Prostate Weight ◽  
Male And Female Rats ◽  
Males And Females ◽  
Normal Males

ABSTRACT The effects of various doses of testosterone propionate (TP) upon the release of luteinizing hormone (LH or ICSH) from the hypophysis of a gonadectomized male or female rat were compared. Prostate weight in hypophysectomized male parabiotic partners was used to evaluate the quantity of circulating LH. Hypophyseal LH was measured by the ovarian ascorbic acid depletion method. Males castrated when 45 days old secreted significantly more LH and had three times the amount of pituitary LH as ovariectomized females. Administration of 25 μg TP daily reduced the amount of LH in the plasma, and increased the amount in the pituitary gland, in both sexes. Treatment with 50 μg caused a further reduction in plasma LH in males, but not in females, while pituitary levels in both were equal to that of their respective controls. LH fell to the same low level in partners of males or females receiving 100 μg TP. When gonadectomized at 39 days, males and females had the same amount of plasma LH, but males had more stored hormone. Pituitary levels were unchanged from controls following treatment with 12.5, 25 or 50 μg TP daily, but plasma values dropped an equal amount in both sexes with the latter two doses. Androgenized males or females, gonadectomized when 39 days old, were very sensitive to the effects of TP and plasma LH was significantly reduced with 12.5 μg daily. Pituitary LH in androgenized males was higher than that of normal males but was reduced to normal by small amounts of TP. The amount of stored LH in androgenized females was not different from that of normal females and it was unchanged by any dose of TP tested. Results are consistent with the conclusion that the male hypothalamic-hypophyseal axis is at least as sensitive as the female axis to the negative feedback effects of TP. Androgenization increases the sensitivity to TP in both males and females.

Effect of Fetal and Neonatal Hypothyroidism on Glucose Tolerance in Middle-Aged Female Rats

2020 ◽  
Vol 20 ◽  
Author(s):  
Sajad Jeddi ◽  
Saeedeh Khalifi ◽  
Mahboubeh Ghanbari ◽  
Asghar Ghasemi
Keyword(s):  
Glucose Tolerance ◽  
Plasma Glucose ◽  
Female Offspring ◽  
Female Rats ◽  
Control Group ◽  
Female Rat ◽  
Middle Aged ◽  
Intravenous Glucose ◽  
Neonatal Hypothyroidism ◽  
Glucose Levels

Background and objective: The effects of hypothyroidism during pregnancy and lactation on carbohydrate metabolism have been mostly studied in male animals. The aim of this study is therefore to investigate effect of fetal and neonatal hypothyroidism (FH and NH) on the glucose tolerance in middle-aged female rat offspring. Methods: Pregnant female rats were divided into three groups: Rats in the control group consumed tap water, while those in the FH and NH groups consumed 250 mg/L of 6-propyl-2-thiouracil (PTU) in their drinking water during gestation or lactation periods, respectively. After weaning, the female offspring were separated and divided into 3 groups (n=8/group): Control, FH, and NH. Body weight was recorded monthly and intravenous glucose tolerance test (IVGTT) was performed at month 12. Results: Compared to controls, female rats in the FH group had significantly higher plasma glucose levels than controls throughout the IVGTT except at min 60. Values at min 5 of the FH and control group were 196.1±1.9 and 155.3±5.9 mg/dL, respectively (P<0.05). In the NH group, plasma glucose levels were significantly higher only at min 5 (185.7±14.1 vs. 155.3±5.9 mg/dL, P<0.05). Conclusion: Hypothyroidism during fetal or neonatal periods caused glucose intolerance in middle-aged female offspring rats.

Sexual Behavior is Enhanced by Regular, Repeated Mating from Young Adulthood to Middle Age in Female Long-Evans Rats

2020 ◽  
Vol 13 (2) ◽  
pp. 169-177
Author(s):  
Fay A. Guarraci ◽  
Chantal M.F. Gonzalez ◽  
Devon Lucero ◽  
Lourdes K. Davis ◽  
Sarah H. Meerts
Keyword(s):  
Sexual Behavior ◽  
Mating Behavior ◽  
Preference Test ◽  
Sexual History ◽  
Female Rats ◽  
Male Rat ◽  
Female Rat ◽  
Repeated Mating ◽  
First Time ◽  
Mating Tests

Background: Aging is associated neuroendocrine changes in women. Animals can be used to model these changes, as well as changes in reproductive behavior. Objective: The current study was designed to characterize mating behavior across age and assess the effects of age and sexual history on mating behavior. Methods: Sexual motivation was assessed using the partner-preference test, in which a female rat is given the choice to interact with a same-sex conspecific or a sexually-vigorous male rat, with which she can mate. Results: Across repeated mating tests (2-12 months of age), female rats spent more time with the male, displayed more solicitation behaviors, were less likely to leave the male after mounts, but visited both stimulus animals less frequently. Comparing a separate group of age-matched, hormoneyoked female rats mated for the first time at 12 months of age to female rats mated for the first time at 2 months of age showed that the 12 month rats visited both stimulus animals less, were less likely to leave the male after mounts, took longer to return to the male after mounts, and displayed fewer solicitation behaviors than their younger counterparts. Relative to middle-aged female rats once they were sexually experienced, 12 month naïve rats spent less time with the male, were more likely to leave the male after mounts, and displayed fewer solicitation behaviors. Furthermore, 12 month naïve rats failed to discriminate between the stimulus animals, visiting both stimulus animals at the same rate unlike 2 month naïve or 12 month experienced rats. Conclusion: Taken together, these results suggest that aging affects some measures of sexual behavior, but most effects of age can be mitigated by regular, repeated mating.

Growth hormone and somatostatin gene expression in pituitary adenomas with active acromegaly and minimal plasma growth hormone elevation

1990 ◽  
Vol 122 (6) ◽  
pp. 745-752 ◽  
Author(s):  
Patrick Pagesy ◽  
Jacques Y. Li ◽  
Françoise Rentier-Delrue ◽  
Olivier Delalande ◽  
Yves Le Bouc ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Northern Blot Analysis ◽  
Secretory Activity ◽  
Ultrastructural Level ◽  
Wide Range ◽  
Igf I ◽  
Gh Gene ◽  
Basal Plasma ◽  
Active Acromegaly ◽  
Plasma Gh

Abstract. Some patients with active acromegaly have elevated plasma IGF-I concentrations with only minimal elevation of plasma GH. We compared adenomatous GH and SRIH expression in 3 such patients (patients No. 1, 2 and 3; basal plasma GH level < 4 μg/l) and in 3 acromegalic patients with high basal plasma GH level (patients No. 4, 5 and 6; 51.7 ± 16.1 μg/l, mean ± sem). By immunocytochemistry, all the tumours proved to be somatotropic adenomas. At the ultrastructural level, signs of low secretory activity were observed in adenomas from patients No. 2 and 3. Perifused adenoma cells of patients No. 1, 2 and 3 released very little GH compared with those of patients No. 4, 5 and 6 (1± 0.37 vs 51.5± 34.1 μg · (10−6 cells) · min−1, p< 0.001). Adenoma SRIH content was 65.7 and 30.6 pg/mg proteins in patients No. 1 and 2, whereas it was undetectable in the others (patients No. 4, 5 and 6). Northern blot analysis showed that the GH gene was poorly expressed in the adenomas from patients No. 1, 2 and 3 compared with the adenomas from patients No. 4, 5 and 6. SRIH mRNA was detected in all 6 adenomas. However, the signal was more intense in the adenomas from patients No. 1, 2 and 3 than in those from patients No. 4, 5 and 6. In conclusion, because of the variability of the biosynthetic and secretory potential of the somatotropic adenomas, patients harbouring this type of pituitary tumours can exhibit a wide range of plasma GH levels. In acromegaly with minimal elevation of plasma GH, the synthesis of SRIH by the adenoma cells themselves could play a role in the inhibition of GH expression.

scholarly journals Increased bioactivation of dihaloalkanes in rat liver due to induction of class Theta glutathione S-transferase T1-1

1998 ◽  
Vol 335 (3) ◽  
pp. 619-630 ◽  
Author(s):  
Philip J. SHERRATT ◽  
Margaret M. MANSON ◽  
Anne M. THOMSON ◽  
Erna A. M. HISSINK ◽  
Gordon E. NEAL ◽  
...  
Keyword(s):  
Western Blotting ◽  
Rat Liver ◽  
Female Rats ◽  
Male Rats ◽  
Male Rat ◽  
Female Rat ◽  
Glutathione S Transferase ◽  
Chemopreventive Agents ◽  
Cytoplasmic Staining ◽  
Potent Inducer

A characteristic feature of the class Theta glutathione S-transferase (GST) T1-1 is its ability to activate dichloromethane and dibromoethane by catalysing the formation of mutagenic conjugates. The level of the GSTT1 subunit within tissues is an important determinant of susceptibility to the carcinogenic effects of these dihaloalkanes. In the present study it is demonstrated that hepatic GST activity towards these compounds can be elevated significantly in female and male Fischer-344 rats by feeding these animals on diets supplemented with cancer chemopreventive agents. Immunoblotting experiments showed that increased activity towards the dihaloalkanes is associated with elevated levels of the GSTT1 subunit in rat liver. Sex-specific effects were observed in the induction of GSTT1 protein. Amongst the chemopreventive agents tested, indole-3-carbinol proved to be the most potent inducer of hepatic GSTT1 in male rats (6.2-fold), whereas coumarin was the most potent inducer of this subunit in the livers of female rats (3.5-fold). Phenobarbital showed significant induction of GSTT1 only in male rat liver and had little effect in female rat liver. Western blotting showed that class Alpha, Mu and Pi GST subunits are not co-ordinately induced with GSTT1, indicating that the expression of GSTT1 is determined, at least in part, by mechanisms distinct from those that regulate levels of other transferases. The increase in amount of hepatic GSTT1 protein was also reflected by an increase in the steady-state level of mRNA in response to treatment with chemopreventive agents and model inducers. Immunohistochemical detection of GSTT1 in rat liver supported the Western blotting data, but showed, in addition to cytoplasmic staining, significant nuclear localization of the enzyme in hepatocytes from some treated animals, including those fed on an oltipraz-containing diet. Significantly, the hepatic level of cytochrome P-450 2E1, an enzyme which offers a detoxification pathway for dihaloalkanes, was unchanged by the various inducing agents studied. It is concluded that the induction of GSTT1 by dietary components and its localization within cells are important factors that should be considered when assessing the risk dihaloalkanes pose to human health.

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