Disruption in the expression and immunolocalisation of steroid receptors and steroidogenic enzymes in letrozole-induced polycystic ovaries in rat

2009 ◽  
Vol 21 (7) ◽  
pp. 827 ◽  
Author(s):  
Francisco M. Zurvarra ◽  
Natalia R. Salvetti ◽  
J. Ian Mason ◽  
Melisa M. L. Velazquez ◽  
Natalia S. Alfaro ◽  
...  
Keyword(s):  
Protein Expression ◽  
Steroid Receptors ◽  
Regulatory Protein ◽  
Female Rats ◽  
Polycystic Ovaries ◽  
Steroidogenic Enzymes ◽  
Serum Lh ◽  
Letrozole Treatment ◽  
Serum Hormone ◽  
Steroidogenic Acute Regulatory

The objective of the present study was to characterise the expression and tissue distribution of steroid receptors (oestrogen receptor-α and –β (ERα, ERβ), androgen receptor (AR) and progesterone receptor (PR)) and steroidogenic enzymes (P450 aromatase (P450arom), 3β-hydroxysteroid dehydrogenase (3β-HSD) and steroidogenic acute regulatory protein (StAR)) in letrozole-induced polycystic ovaries of rats. Changes in serum hormone levels, protein expression in whole ovaries by western blot analysis and protein localisation by immunohistochemistry were determined in female rats treated with the aromatase inhibitor letrozole and compared with controls in proestrous and diestrous rats. Increases in the serum LH, FSH and testosterone concentrations were observed in letrozole-treated rats whereas serum oestradiol and progesterone levels were reduced. Protein expression as analysed by western immunoblot was consistent with the immunohistochemical data. Letrozole treatment induced an increase in the expression of AR, StAR and 3β-HSD and a decrease in ERβ. ERα, PR and P450arom showed partial changes in relation to some cycle stages. These results indicate that cystogenesis in this experimental model is characterised by changes in steroid receptors and steroidogenic enzyme expression that may be essential to proper ovarian functioning and are in agreement with similar changes observed in women with PCOS.

2040-P: Chronic Activation of CREB by Islet Amyloid Increases Star (Steroidogenic Acute Regulatory Protein) Expression in Islets

Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 2040-P
Author(s):  
MEGHAN F. HOGAN ◽  
NATHALIE ESSER ◽  
ANDREW T. TEMPLIN ◽  
JOSEPH J. CASTILLO ◽  
SAKENEH ZRAIKA ◽  
...  
Keyword(s):  
Protein Expression ◽  
Regulatory Protein ◽  
Steroidogenic Acute Regulatory Protein ◽  
Islet Amyloid ◽  
Chronic Activation ◽  
Steroidogenic Acute Regulatory

scholarly journals Development of an experimental ovarian tumor: immunocytochemical analysis

2002 ◽  
pp. 387-395 ◽  
Author(s):  
E Sorianello ◽  
S Fritz ◽  
C Beyer ◽  
DB Hales ◽  
A Mayerhofer ◽  
...  
Keyword(s):  
Granulosa Cells ◽  
Regulatory Protein ◽  
Tumor Development ◽  
Female Rats ◽  
Nuclear Antigen ◽  
Normal Ovary ◽  
Rt Pcr ◽  
Thecal Cells ◽  
Junction Protein ◽  
Steroidogenic Acute Regulatory

OBJECTIVE: The aim of the present work was to study whether immunocytochemical parameters present in the normal ovary were altered after tumor development under high gonadotropin levels. METHODS: Ovarian tumors (luteoma): castrated female rats had an ovary grafted into the spleen; tumors were left to develop for 1, 2, 3 or 7 months. The presence of apoptotic cells (TUNEL method) and the expression of proliferating cell nuclear antigen (PCNA), gap junction protein (Cx43), steroidogenic acute regulatory protein (StAR), aromatase and synaptosome-associated protein of 25 kDa (SNAP-25) were determined by immunocytochemistry. Some of these findings were confirmed by RT-PCR (Cx43, StAR, SNAP-25). Inhibin subunit mRNAs were investigated by Northern blot. RESULTS: PCNA staining of tumors was mainly found in granulosa cells of transforming follicles and was absent from luteinized follicles. A nearly complete absence of apoptosis was observed. Cx43 was mainly found in follicles, while it was very weakly expressed or absent in luteinized follicles. StAR protein expression, indicating active steroidogenesis, was demonstrated only in luteinized follicles and in thecal cells, but was absent from granulosa cells. Aromatase immunoreactivity was very intense in granulosa and also present in luteal cells. Membrane-associated and cytoplasmic SNAP-25 immunostaining was determined in patches of endocrine cells in the follicles, as well as in the luteinized follicles. The expression of mRNAs for Cx43, StAR and SNAP-25 (RT-PCR) and inhibin subunits (Northern blots) were confirmed in 1-, 3- and 7-month-old tumors. CONCLUSIONS: These results indicated that luteoma most likely develop from unruptured follicles by hypertrophy and proliferation of follicular cells. Circulating gonadotropins seem to play a fundamental role in maintaining the expression of proteins typically expressed in normal ovary, while avoiding apoptosis in this tissue.

scholarly journals Luteinizing Hormone/Human Chorionic Gonadotropin-Mediated Activation of mTORC1 Signaling Is Required for Androgen Synthesis by Theca-Interstitial Cells

2012 ◽  
Vol 26 (10) ◽  
pp. 1732-1742 ◽  
Author(s):  
Murugesan Palaniappan ◽  
K. M. J. Menon
Keyword(s):  
Chorionic Gonadotropin ◽  
Regulatory Protein ◽  
Steroidogenic Acute Regulatory Protein ◽  
Steroidogenic Enzymes ◽  
Steroidogenic Enzyme ◽  
S6 Kinase ◽  
Ribosomal Protein S6 ◽  
Mtorc1 Signaling ◽  
Steroidogenic Acute Regulatory ◽  
I Cells

Abstract LH triggers the biosynthesis of androgens in the theca-interstitial (T-I) cells of ovary through the activation of a cAMP-dependent pathway. We have previously shown that LH/human chorionic gonadotropin (hCG) activates mammalian target of rapamycin complex 1 (mTORC1) signaling network, leading to cell proliferation. In the present study, we provide evidence that the LH/hCG-mediated activation of the mTORC1 signaling cascade is involved in the regulation of steroidogenic enzymes in androgen biosynthesis. Treatment with LH/hCG increased the expression of downstream targets of mTORC1, ribosomal protein S6 kinase 1, and eukaryotic initiation factor 4E as well as steroidogenic enzymes. LH/hCG-mediated stimulation of the steroidogenic enzyme mRNA was blocked by the mTORC1 inhibitor, rapamycin. This inhibitory effect was selective because rapamycin failed to block hCG-mediated increase in the expression of Star mRNA levels. Furthermore, pharmacological targeting of mTORC1 with rapamycin also blocked LH/hCG- or forskolin-induced expression of cAMP response element-binding protein (CREB) and steroidogenic enzymes (P450 side-chain cleavage enzyme, 3β-hydroxysteroid dehydrogenase type 1, and 17α-hydroxylase/17,20 lyase) but produced no effect on steroidogenic acute regulatory protein levels. These results were further confirmed by demonstrating that the knockdown of mTOR using small interfering RNA selectively abrogated the LH/hCG-induced increase in steroidogenic enzyme expression, without affecting steroidogenic acute regulatory protein expression. LH/hCG-stimulated androgen production was also blocked by rapamycin. Furthermore, the pharmacological inhibition of mTORC1 or ribosomal protein S6 kinase 1 signaling prevented the LH/hCG-induced phosphorylation of CREB. Chromatin immunoprecipitation assays revealed the association of CREB with the proximal promoter of the Cyp17a1 gene in response to hCG, and this association was reduced by rapamycin treatment. Taken together, our findings show for the first time that LH/hCG-mediated activation of androgen biosynthesis is regulated by the mTORC1 signaling pathway in T-I cells.

CIRCADIAN FLUCTUATIONS OF SERUM HORMONE LEVELS IN PREPUBERTAL MALE AND FEMALE RATS

1976 ◽  
Vol 83 (2) ◽  
pp. 269-279 ◽  
Author(s):  
K. D. Döhler ◽  
W. Wuttke
Keyword(s):  
Age Groups ◽  
Serum Testosterone ◽  
Female Rats ◽  
Serum Prolactin ◽  
Male And Female ◽  
Hormone Levels ◽  
Male And Female Rats ◽  
Serum Lh ◽  
Serum Hormone ◽  
Old Females

ABSTRACT Diurnal variations in serum hormone levels during 2 different stages of prepubertal development were investigated in male and female rats. Groups of 13 to 18 and 25 to 30 day old male and female rats were decapitated at 4-hour by intervals during a period of 24 h. Their blood was collected and hormones were measured by radio-immunoassay. FSH levels were constantly high in 13 to 18, but low in 25 to 30 day old females. FSH was low in younger males, and significantly higher but without diurnal fluctuations in the older males. Serum LH was low in approximately 40% of the 13 to 18 day old females, while 40% had moderately high levels, and the remaining females extremely high levels of the hormone. Most of the extremely high LH peaks were found at 15.00 h and some at 03.00 h. Older females and males of both age groups had constantly low serum LH levels. Serum oestradiol was high in males and females during days 13 to 18, but it was lower in the 25 to 30 day old animals. In the young females prolactin was slightly elevated between 15.00 h and 19.00 h, while in the males the serum prolactin fluctuations were not significant. Serum testosterone was low in females at all times. The 13 to 18 day old males had higher testosterone levels than the 25 to 30 day old males. Both groups showed slight, but insignificant fluctuations in serum testosterone. These results confirm result published previously and furthermore they demonstrate the existence of circasemedian or circadian rhythms for both the gonadotrophins and gonadal steroids. These results, also suggest that the maturation of the positive feedback action of oestradiol on gonadotrophin release in female rats occurs between day 10 and 20.

130-OR: Statin Exposure Increases Star (Steroidogenic Acute Regulatory Protein) Expression in Islets: A Novel Mechanism for ß-Cell Dysfunction and Increased Diabetes Risk?

Diabetes ◽  
2021 ◽  
Vol 70 (Supplement 1) ◽  
pp. 130-OR
Author(s):  
MEGHAN F. HOGAN ◽  
NATHALIE ESSER ◽  
ANDREW T. TEMPLIN ◽  
JOSEPH J. CASTILLO ◽  
REHANA AKTER ◽  
...  
Keyword(s):  
Protein Expression ◽  
Regulatory Protein ◽  
Diabetes Risk ◽  
Steroidogenic Acute Regulatory Protein ◽  
Cell Dysfunction ◽  
Steroidogenic Acute Regulatory
Sign in / Sign up

Export Citation Format

Share Document