THE DEVELOPMENT OF A FEEDBACK MECHANISM BETWEEN THE OVARY AND THE DIENCEPHALIC-HYPOPHYSIAL SYSTEM IN THE RAT

1963 ◽  
Vol 26 (2) ◽  
pp. 287-NP ◽  
Author(s):  
J. PRESL ◽  
J. HORSKÝ ◽  
M. HENZL ◽  
J. JIRÁSEK
Keyword(s):  
Anterior Pituitary ◽  
Anterior Lobe ◽  
Feedback Mechanism ◽  
Histological Structure ◽  
Histological Investigation ◽  
Basic Information ◽  
Ovarian Weight ◽  
The Difference ◽  
Golgi Zone ◽  
Mucoid Cells

SUMMARY With the object of obtaining basic information concerning the establishment of the feedback mechanism between the ovaries and the diencephalic-hypophysial system (DHS), changes in the gonadotrophic activity and histological structure of the anterior pituitary lobe were determined in groups of rats 21 days following ovariectomy on the day of birth or at 5, 10, 15, 20, 30 and 50 days. It was shown that the gonadotrophic activity of the hypophysis of spayed females and non-spayed controls differed using the criterion of uterine weight of the recipient, following ovariectomy at birth. After spaying at the age of 5 days the difference was also statistically significant using the criterion of ovarian weight. Histological investigation showed that in animals ovariectomized at days 1 and 5 there was an increase in PAS-positive mucoid cells in the adenohypophysis with a distinct PAS-positive Golgi zone in the pale centre of the cytoplasm. The results of these experiments show that a feedback mechanism between the ovaries and the DHS becomes established at an age between (21–x) and (26–x) days, where x is the period necessary for the development of demonstrable post-castration changes in the anterior lobe. In view of the reported initiation of ovarian oestrogen production, the hypothesis is discussed that the feedback mechanism begins to function during very early post-natal life.

Ultrastructural morphology of nontumorous lactotrophs in human pituitaries exposed to high prolactin levels

1987 ◽  
Vol 45 ◽  
pp. 896-897
Author(s):  
S. Jalalah ◽  
K. Kovacs ◽  
E. Horvath
Keyword(s):  
Anterior Pituitary ◽  
Secretory Activity ◽  
Pituitary Hormones ◽  
Feedback Mechanism ◽  
Endocrine Activity ◽  
Hormone Synthesis ◽  
Anterior Pituitary Hormones ◽  
Negative Feedback Mechanism ◽  
Ultrastructural Morphology ◽  
Transmission Electron

Lactotrophs, as many other endocrine cells, change their morphology in response to factors influencing their secretory activity. Secretion of prolactin (PRL) from lactotrophs, like that of other anterior pituitary hormones, is under the control of the hypothalamus. Unlike most anterior pituitary hormones, PRL has no apparent target gland which could modulate the endocrine activity of lactotrophs. It is generally agreed that PRL regulates its own release from lactotrophs via the short loop negative feedback mechanism exerted at the level of the hypothalamus or the pituitary. Accordingly, ultrastructural morphology of lactotrophs is not constant; it is changing in response to high PRL levels showing signs of suppressed hormone synthesis and secretion.By transmission electron microscopy and morphometry, we have studied the morphology of lactotrophs in nontumorous (NT) portions of 7 human pituitaries containing PRL-secreting adenoma; these lactotrophs were exposed to abnormally high PRL levels.

scholarly journals 152. Applying A Difference-in-Difference Analysis to Assess Effect of Antimicrobial Stewardship Strategies on Changes in Antimicrobial Use

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S86-S86
Author(s):  
Ann F Chou ◽  
Yue Zhang ◽  
Makoto M Jones ◽  
Christopher J Graber ◽  
Matthew B Goetz ◽  
...  
Keyword(s):  
Antimicrobial Stewardship ◽  
Clinical Pharmacist ◽  
Antibiotic Use ◽  
Feedback Mechanism ◽  
Health Care Facilities ◽  
Antimicrobial Use ◽  
Time Points ◽  
The Difference ◽  
The Impact ◽  
Over Time

Abstract Background About 30–50% of inpatient antimicrobial therapy is sub-optimal. Health care facilities have utilized various antimicrobial stewardship (AS) strategies to optimize appropriate antimicrobial use, improve health outcomes, and promote patient safety. However, little evidence exists to assess relationships between AS strategies and antimicrobial use. This study examined the impact of changes in AS strategies on antimicrobial use over time. Methods This study used data from the Veterans Affairs (VA) Healthcare Analysis & Informatics Group (HAIG) AS survey, administered at 130 VA facilities in 2012 and 2015, and antimicrobial utilization from VA Corporate Data Warehouse. Four AS strategies were examined: having an AS team, feedback mechanism on antimicrobial use, infectious diseases (ID) attending physicians, and clinical pharmacist on wards. Change in AS strategies were computed by taking the difference in the presence of a given strategy in a facility between 2012–2015. The outcome was the difference between antimicrobial use per 1000 patient days in 2012–2013 and 2015–2016. Employing multiple regression analysis, changes in antimicrobial use was estimated as a function of changes in AS strategies, controlling for ID human resources in and organizational complexity. Results Of the 4 strategies, only change in availability of AS teams had an impact on antimicrobial use. Compared to facilities with no AS teams at both time points, antibiotic use decreased by 63.9 uses per 1000 patient days in facilities that did not have a AS team in 2012 but implemented one in 2015 (p=0.0183). Facilities that had an AS team at both time points decreased use by 62.2 per 1000 patient days (p=0.0324). Conclusion The findings showed that AS teams reduced inpatient antibiotic use over time. While changes in having feedback on antimicrobial use and clinical pharmacist on wards showed reduced antimicrobial use between 2012–2015, the differences were not statistically significant. These strategies may already be a part of a comprehensive AS program and employed by AS teams. In further development of stewardship programs within healthcare organizations, the association between AS teams and antibiotic use should inform program design and implementation. Disclosures All Authors: No reported disclosures

Factors Influencing Diuresis in Rats Following Total-Body X-Irradiation

1957 ◽  
Vol 189 (1) ◽  
pp. 11-14 ◽  
Author(s):  
E. Irene Pentz ◽  
Robert J. Hasterlik
Keyword(s):  
Adrenal Cortex ◽  
Anterior Pituitary ◽  
Adrenal Glands ◽  
Anterior Lobe ◽  
Posterior Pituitary ◽  
Cortical Control ◽  
Factors Influencing ◽  
X Irradiation ◽  
Diuretic Response ◽  
Total Body

An immediate diuresis has been observed in rats exposed to total-body x-irradiation ranging between 100 and 400 r. Since the highest dosage produced more consistent results, it was used in conjunction with extirpation of various glands and other organs in an effort to determine the mechanism that responds so promptly to x-irradiation. The anterior pituitary and the adrenal cortex are of prime importance in this reaction. Removal of the anterior lobe of the pituitary or removal of the adrenal glands is sufficient to completely inhibit diuresis following 400 r x-irradiation. This diuretic response is not dependent upon the presence of the posterior pituitary since animals having only this gland removed became diuretic following exposure to 400 r. The evidence suggests that the release of antidiuretic substances from tissues other than the posterior pituitary is under anterior pituitary-adrenal cortical control.

271. Effect of season on sow ovarian morphology

2008 ◽  
Vol 20 (9) ◽  
pp. 71
Author(s):  
M. Bertoldo ◽  
P. K. Holyoake ◽  
G. Evans ◽  
C. G. Grupen
Keyword(s):  
Ovarian Tissue ◽  
Developmental Competence ◽  
Corpora Lutea ◽  
Ovarian Weight ◽  
Antral Follicles ◽  
Oocyte Developmental Competence ◽  
Ovarian Morphology ◽  
The Difference ◽  
Seasonal Infertility ◽  
Farrowing Rate

Reduced farrowing rate caused by embryonic mortality is a manifestation of seasonal infertility in pigs. The ability of the oocyte to mature, be fertilised and sustain embryonic development is acquired gradually by the oocyte throughout folliculogenesis. This study was undertaken to determine if seasonal differences in ovarian morphology are associated with reduced reproductive performance displayed during seasonal infertility. Sows culled after weaning were sourced from two genetically distinct herds (Farms A and B). Pairs of ovaries were collected from sows 4 days post-weaning during winter (n = 131) and summer (n = 275). Ovarian weight (Farm A only) and the numbers of small (3–4 mm) and large (5–8 mm) follicles were assessed (Farms A and B). Data did not follow normality and was analysed using the Mann–Whitney test. Mean ovarian weight per sow during winter (20.0 ± 1.3 g) was significantly heavier than that during summer (15.3 ± 0.8 g; P < 0.05). Farm A ovaries had a greater total number of antral follicles in winter compared with summer, and a greater number of antral follicles in winter compared with Farm B ovaries (P < 0.05). In Farm A ovaries, the proportion of follicles that were large was greater in summer compared with winter (78% v. 66%; P < 0.05), but the follicular distribution did not change with season in Farm B ovaries. While the findings demonstrate that ovarian weight was greater in winter compared with summer, they suggest that this difference was not the result of changes in the number or distribution of surface antral follicles. The difference in ovarian weight is possibly due to differences in ovarian tissue resulting from regressed corpora lutea. Further studies are being undertaken to assess the effect of season on oocyte developmental competence and the steroid content of follicular fluid isolated from small and large follicles.

Differences in network centrality between high and low myopia: a voxel-level degree centrality study

2020 ◽  
Vol 61 (10) ◽  
pp. 1388-1397
Author(s):  
Yi Cheng ◽  
Li Yan ◽  
Liqun Hu ◽  
Hongyun Wu ◽  
Xin Huang ◽  
...  
Keyword(s):  
Brain Activity ◽  
Inferior Frontal Gyrus ◽  
Brain Regions ◽  
Anterior Lobe ◽  
Parahippocampal Gyrus ◽  
Functional Networks ◽  
Degree Centrality ◽  
Left Caudate ◽  
The Difference ◽  
The Right

Background Previous studies have linked high myopia (HM) to brain activity, and the difference between HM and low myopia (LM) can be assessed. Purpose To study the differences in functional networks of brain activity between HM and LM by the voxel-level degree centrality (DC) method. Material and Methods Twenty-eight patients with HM (10 men, 18 women), 18 patients with LM (4 men, 14 women), and 59 healthy controls (27 men, 32 women) were enrolled in this study. The voxel-level DC method was used to assess spontaneous brain activity. Correlation analysis was used to explore the change of average DC value in different brain regions, in order to analyze differences in brain activity between HM and LM. Results DC values of the right cerebellum anterior lobe/brainstem, right parahippocampal gyrus, and left caudate in HM patients were significantly higher than those in LM patients ( P < 0.05). In contrast, DC values of the left medial frontal gyrus, right inferior frontal gyrus, left middle frontal gyrus, and left inferior parietal lobule were significantly lower in patients with HM ( P < 0.05). However, there was no correlation between behavior and average DC values in different brain regions ( P < 0.05). Conclusion Different changes in brain regions between HM and LM may indicate differences in neural mechanisms between HM and LM. DC values could be useful as biomarkers for differences in brain activity between patients with HM and LM. This study provides a new method to assess differences in functional networks of brain activity between patients with HM and LM.

Discovery of the luteinizing hormone of the anterior pituitary gland

2004 ◽  
Vol 287 (5) ◽  
pp. E818-E819 ◽  
Author(s):  
H. Maurice Goodman
Keyword(s):  
Luteinizing Hormone ◽  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Anterior Lobe ◽  
Anterior Pituitary Gland ◽  
Luteinizing Hormones ◽  
Historical Significance ◽  
Classic Paper

This essay looks at the historical significance of an APS classic paper that is freely available online: Fevold HL, Hisaw FL, Leonard SL. The gonad stimulating and the luteinizing hormones of the anterior lobe of the hypophesis. Am J Physiol 97: 291—301, 1931 ( http://ajplegacy.physiology.org/cgi/reprint/97/2/291 ).

CYTOLOGICAL AND CYTOCHEMICAL COMPARATIVE STUDY ON THE EFFECT OF CYPROTERONE (ANTI-ANDROGEN) AND GONADECTOMY ON THE GONADOTROPHIC CELLS OF THE HYPOPHYSIS IN MALE RATS

1969 ◽  
Vol 61 (2) ◽  
pp. 293-301 ◽  
Author(s):  
Kazimierz Mietkiewski ◽  
Ludwik Malendowicz ◽  
Andrzej Lukaszyk
Keyword(s):  
Acid Phosphatase ◽  
Comparative Study ◽  
Adaptive Systems ◽  
Competitive Inhibitor ◽  
Anterior Lobe ◽  
Male Rats ◽  
Mucoid Cells ◽  
Gonadotrophic Cells

ABSTRACT Cyproterone, a competitive inhibitor of testosterone, injected into male rats in daily doses of 10 mg, induces hypertrophy and hyperplasia of the mucoid cells of the hypophysis, followed by the appearance of castration cells. The largest number of these cells is observed on the 12th test-day. These changes are accompanied by degranulation of mucoid cells and an increase in the reactions for acid phosphatase and non-specific esterases. As the injection of cyproterone is continued, the number of castration cells in the anterior lobe of the hypophysis decreases and the cytoenzymic reactions observed show a fall in intensity. Gonadectomy, on the contrary, brings about lasting characteristic changes in the anterior lobe of the hypophysis, which mainly consist in the occurrence of castration cells accompanied by an increase in the intensity of reactions for acid phosphatase and non-specific esterases. The above data suggest that in the course of administration of cyproterone, suitable adaptive systems develop in the organism which inhibit the action of this anti-androgen.

Inhibition of release of a novel pituitary polypeptide, 7B2, follicle-stimulating hormone, and luteinizing hormone from rat anterior pituitary cells in vitro by human β-inhibin

1986 ◽  
Vol 64 (9) ◽  
pp. 1259-1262 ◽  
Author(s):  
John S. D. Chan ◽  
Jie-Ying Deng ◽  
Anoop K. Brar ◽  
Nabil G. Seidah ◽  
Michel Chrétien
Keyword(s):  
Luteinizing Hormone ◽  
Anterior Pituitary ◽  
Polyclonal Antibodies ◽  
Follicle Stimulating Hormone ◽  
Feedback Mechanism ◽  
Pituitary Cells ◽  
Anterior Pituitary Cells ◽  
Specific Radioimmunoassay ◽  
Stimulating Hormone

We have recently purified a novel pituitary polypeptide designated 7B2. By raising polyclonal antibodies to a synthetic 7B2 fragment in rabbits, we have developed a sensitive and specific radioimmunoassay for this novel polypeptide, and it has been used for the study of the release of immunoreactive 7B2 from rat anterior pituitary cells in vitro. In addition, immunocytochemical study shows that 7B2 is present in the gonadotropin cells of rat anterior pituitary. The aim of the present studies is to investigate the effect of human β-inhibin, testosterone, and combined testosterone plus human β-inhibin on the induced release of immunoreactive 7B2, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) in rat anterior pituitary cell culture in vitro. Our results show that both human β-inhibin and testosterone effectively suppress the stimulatory effect of luteinizing hormone-releasing hormone (LHRH) on immunoreactive 7B2, FSH, and LH release. The present data indicate that the regulation of secretion of 7B2 and pituitary gonadotropins may be under a similar type of feedback mechanism.

scholarly journals Prolactin secretory rhythm of mated rats induced by a single injection of oxytocin

2006 ◽  
Vol 290 (3) ◽  
pp. E566-E572 ◽  
Author(s):  
Marcel Egli ◽  
Richard Bertram ◽  
Natalia Toporikova ◽  
Michael T. Sellix ◽  
Wilfredo Blanco ◽  
...  
Keyword(s):  
Single Injection ◽  
Anterior Lobe ◽  
Time Of Day ◽  
Feedback Mechanism ◽  
Network Function ◽  
Ovx Rats ◽  
Inhibitory Feedback ◽  
Additional Feedback ◽  
Secretory Pattern ◽  
Da Release

Mating or vaginocervical stimulation [copulatory stimulus (CS)] induces two daily surges of the hormone prolactin (PRL) in rats. This unique secretory pattern of PRL surges is characteristic for the first half of pregnancy and is also present in ovariectomized (OVX) rats. Studies have shown that CS additionally provokes an acute release of the hormone oxytocin (OT). In this study, we tested whether a single injection of OT (iv) is sufficient to initiate the PRL secretion pattern of OVX/CS rats. Furthermore, we measured the 24-h profile of dopamine (DA) content in the anterior lobe of the pituitary gland, because DA is the major inhibitory factor of PRL secretion. The results indicated that a single injection of OT induces a PRL secretory rhythm and a DA release pattern similar to that initiated by CS. Immunocytochemical investigation showed that particular OTergic neurons in the hypothalamus express receptors for PRL, as well as for vasoactive intestinal polypeptide, which indicates an involvement in generating the PRL rhythm and entraining it to the ambient photoperiod. On the basis of this study, we suggest that the PRL-DA inhibitory feedback loop between lactotrophs and DAergic neurons plays a crucial role in generating the oscillatory PRL secretion pattern in CS rats. A timing signal, likely provided by the hypothalamic suprachiasmatic nucleus, entrains the autonomous PRL oscillation to a particular time of day. Mathematical modeling was used to illustrate the proposed network function. The experimental results further suggest an additional feedback mechanism in which certain hypothalamic OTergic neurons are influenced by PRL.

scholarly journals Role of PROP1 in Pituitary Gland Growth

2005 ◽  
Vol 19 (3) ◽  
pp. 698-710 ◽  
Author(s):  
Robert D. Ward ◽  
Lori T. Raetzman ◽  
Hoonkyo Suh ◽  
Brandon M. Stone ◽  
Igor O. Nasonkin ◽  
...  
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Anterior Lobe ◽  
Clinical Findings ◽  
Proliferative Potential ◽  
Rathke’S Pouch ◽  
Rathke's Pouch ◽  
Pituitary Hyperplasia ◽  
Dividing Cells ◽  
Pituitary Hypoplasia

Abstract Mutations in the PROP1 transcription factor gene lead to reduced production of thyrotropin, GH, prolactin, and gonadotropins as well as to pituitary hypoplasia in adult humans and mice. Some PROP1-deficient patients initially exhibit pituitary hyperplasia that resolves to hypoplasia. To understand this feature and to explore the mechanism whereby PROP1 regulates anterior pituitary gland growth, we carried out longitudinal studies in normal and Prop1-deficient dwarf mice from early embryogenesis through adulthood, examining the volume of Rathke’s pouch and its derivatives, the position and number of dividing cells, the rate of apoptosis, and cell migration by pulse labeling. The results suggest that anterior pituitary progenitors normally leave the perilumenal region of Rathke’s pouch and migrate to form the anterior lobe as they differentiate. Some of the cells that seed the anterior lobe during organogenesis have proliferative potential, supporting the expansion of the anterior lobe after birth. Prop1-deficient fetal pituitaries are dysmorphic because mutant cells are retained in the perilumenal area and fail to differentiate. After birth, mutant pituitaries exhibit enhanced apoptosis and reduced proliferation, apparently because the mutant anterior lobe is not seeded with progenitors. These studies suggest a mechanism for Prop1 action and an explanation for some of the clinical findings in human patients.

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