In vitro steroid production in the postovulatory follicles of the amago salmon,Oncorhynchus rhodurus, in response to salmon gonadotropin

1982 ◽  
Vol 219 (1) ◽  
pp. 105-109 ◽  
Author(s):  
Yoshitaka Nagahama ◽  
Hirohiko Kagawa
Keyword(s):  
Steroid Production ◽  
Amago Salmon

266 Effects of Inflammatory States on Ovarian Biology and Oocyte Competence

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 134-135
Author(s):  
Jennifer A Hernandez Gifford ◽  
Emily Ferranti ◽  
Kylee Forrest ◽  
Craig A Gifford
Keyword(s):  
Granulosa Cell ◽  
Oocyte Maturation ◽  
Beta Catenin ◽  
Control Mechanisms ◽  
Steroid Production ◽  
Oocyte Competence ◽  
Nuclear Maturation ◽  
Naturally Occurring ◽  
Hormonal Milieu

Abstract Female fertility is dependent on estradiol concentrations which regulate a multitude of ovarian functions including follicle development and oocyte maturation leading to ovulation of a viable oocyte. Estradiol biosynthesis is regulated by coordinated actions of follicle-stimulating hormone and intra-ovarian control mechanisms including the co-transcription factor beta-catenin. Beta-catenin is a multi-faceted protein recognized for its role in granulosa cell steroid production and is shown to be modulated by lipopolysaccharide (LPS), the endotoxin responsible for stimulation of the immune system in infections caused by Gram-negative bacteria. Beef heifers treated with subacute concentrations of LPS during a synchronized follicular wave demonstrate a decline in serum estradiol concentrations 50 h after CIDR withdrawal, corresponding with dominant follicle maturation and preceding ovulation. The endotoxin exposure also resulted in increased LPS concentration and E2:P4 ratios in follicular fluid suggesting that low dose LPS modulates the intra-follicular hormonal milieu. Additionally, in a granulosa cell line, LPS treatment decreased mRNA expression of aromatase and beta-catenin. These data indicate that LPS alters E2 synthesis by modulating beta-catenin and subsequent steroidogenic enzyme expression. To further explore the contribution of naturally occurring LPS exposure on follicular steroid production and developing oocytes, bovine ovary pairs were collected from local abattoirs. Oocytes were aspirated from small follicles and matured in vitro to evaluate meiotic events related to nuclear maturation and spindle morphology. Small follicles from ovarian pairs were separated by the detectable LPS concentrations into high and low LPS groups. Oocytes matured from low LPS follicles demonstrated an increase in the percent of abnormal maturation events. Data indicate that induced or naturally occurring low doses of LPS can alter circulating and follicular estradiol concentrations impairing oocyte maturation. Perturbation to local ovarian signaling cascades from subclinical inflammatory disease may be an unappreciated factor altering fertility and leading to decreased cow retention.

Follicular steroidogenesis in vitro in cyclic and PMSG/hCG-treated gilts

1991 ◽  
Vol 71 (4) ◽  
pp. 1257-1260
Author(s):  
T. Wiesak ◽  
R. T. Hardin ◽  
G. R. Foxcroft ◽  
M. G. Hunter
Keyword(s):  
Key Words ◽  
Follicular Development ◽  
Steroid Production ◽  
Functional Differences ◽  
Key Words Pig

Basal steroid production in vitro by comparable follicles from cyclic and PMSG/hCG-treated gilts was similar. Follicular responses to LH in vitro varied, however, confirming earlier evidence for functional differences in the pattern of follicular development in immature gilts in response to exogenous gonadotropins compared with naturally cyclic gilts. Key words: Pig, gonadotrophin, follicle, steroidogenesis, steroids

GnRH antagonist inhibition of gonadotropin and steroid secretion in boars in vivo and steroid production in vitro.

2000 ◽  
Vol 78 (6) ◽  
pp. 1591 ◽  
Author(s):  
E L Zanella ◽  
D D Lunstra ◽  
T H Wise ◽  
J E Kinder ◽  
J J Ford
Keyword(s):  
Gnrh Antagonist ◽  
Steroid Production ◽  
Steroid Secretion

Effect of difluoromethylornithine on the LH surge and subsequent ovulation in the rat

1988 ◽  
Vol 117 (3) ◽  
pp. 447-453 ◽  
Author(s):  
S. A. Nicholson ◽  
M. Aslam ◽  
T. T. Chuang ◽  
B. Gillham ◽  
M. T. Jones
Keyword(s):  
Ornithine Decarboxylase ◽  
Plasma Concentrations ◽  
Specific Inhibitor ◽  
Steroid Production ◽  
Lh Surge ◽  
Direct Observations ◽  
Steroid Dependent ◽  
Lh Release ◽  
Plasma Oestradiol

ABSTRACT Female Wistar-derived rats with regular oestrous cycles were injected s.c. at 15.00 h on pro-oestrus with difluoromethylornithine (DFMO), a specific inhibitor of ornithine decarboxylase. The drug (10–100 mg/rat) caused a dose-related reduction in the concentration of LH in plasma taken at 19.00 h (the time of the peak of the LH surge in this colony). There was also a dose-related reduction in the pituitary content of total polyamines. The reduction in the plasma concentration of LH was not due to the shifting of the time of the peak of the surge, as concentrations were significantly lower than control from 17.00 to 21.00 h, the overall reduction in total LH release being approximately 50%. The number of ova in the oviducts at 06.00 h next morning was significantly reduced by treatment with 50 mg DFMO/rat, by an average of 70%. Injection of DFMO enhanced the fall in plasma oestradiol concentrations seen between 15.00 and 19.00 h, in a dose-related manner. It also prevented the rise in progesterone concentrations seen in control animals during this period. The ability of DFMO to prevent the rise in plasma concentrations of LH was not secondary to the effects of the drug on ovarian steroid production because DFMO also significantly reduced the LH surge in animals ovariectomized on dioestrus and given appropriate replacement injections of oestradiol and progesterone. It seems possible that part of the action of DFMO is exercised at the hypothalamus, since when 50 mg DFMO/rat was given either 2 or 4 h before the expected peak of the LH surge, the LHRH content of the hypothalamus was significantly reduced at that time. These results suggest that activation of ornithine decarboxylase is a necessary prerequisite for a normal LH surge, and that this activation is steroid-dependent. This conclusion is borne out by results from direct observations on the activity of the enzyme in pituitary tissue incubated in vitro. J. Endocr. (1988) 117, 447–453

Secretory patterns of 1α-hydroxycorticosterone in the isolated perifused interrenal gland of the dogfish, Scyliorhinus canicula

1990 ◽  
Vol 5 (1) ◽  
pp. 55-60 ◽  
Author(s):  
L. B. O'Toole ◽  
K.J. Armour ◽  
C. Decourt ◽  
N. Hazon ◽  
B. Lahlou ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Significant Rise ◽  
Dependent Manner ◽  
Steroid Production ◽  
Secretory Rate ◽  
Scyliorhinus Canicula ◽  
Interrenal Gland ◽  
Dose Dependent ◽  
Stimulation Of

ABSTRACT An isolated in-vitro perifused interrenal gland preparation from the dogfish Scyliorhinus canicula was used to study production of quantitatively the major corticosteroid 1α-hydroxycorticosterone (1α-OH-B), measured by radioimmunoassay. Basal secretory rates were 877·1 ± 145 (s.e.m.) fmol/mg per 15 min (n=14) and the preparation remained viable for up to 22 h, as reflected in a brisk response to 10 μm cyclic AMP (cAMP) after this time. Steroid production responded in a dose-dependent manner to porcine ACTH, with 10 μm producing a maximum stimulation of 225% above the basal secretory rate. cAMP (10 μm) produced an increase of 278% above basal, while 1 μm forskolin increased basal secretory rates by 127%. [Val5]- and [Ile5]-angiotensin II (0·1 μm) increased 1α-OH-B production by 120 and 372% respectively over basal secretory rates. Increasing the concentration of K+ in the perfusate from 8 mm to 12, 18, 28 and 40 mm produced a significant rise only at 28 mm. Alterations in the concentration of Na+ and osmolarity of the perifusion medium had inconsistent effects on steroid production. Increased concentrations of urea (from 360 to 720 mm) increased the basal secretory rate by 121%, whilst reducing the concentration of urea (from 360 to 90 mm) had no effect.

In vitro steroid production by triploid ovarian follicles

2003 ◽  
Vol 133 (3) ◽  
pp. 279-286 ◽  
Author(s):  
D. Schafhauser-Smith ◽  
T.J. Benfey
Keyword(s):  
Ovarian Follicles ◽  
Steroid Production

STUDIES ON THE MECHANISM OF SECRETION OF CORTICOSTEROIDS BY THE ISOLATED PERFUSED ADRENAL OF THE RAT

1981 ◽  
Vol 91 (2) ◽  
pp. 313-323 ◽  
Author(s):  
C. P. SIBLEY ◽  
B. J. WHITEHOUSE ◽  
G. P. VINSON ◽  
C. GODDARD ◽  
E. McCREDIE
Keyword(s):  
Culture Medium ◽  
Ion Concentration ◽  
Acth Stimulation ◽  
Steroid Production ◽  
Simple Diffusion ◽  
Corticosterone Secretion ◽  
Complex Process ◽  
Doc Production ◽  
Different Levels

A technique for the perfusion of the rat adrenal cortex is described. With tissue culture Medium 199 the preparation was responsive in terms of steroid production to both ACTH and K+ ions. Production of corticosterone and 18-hydroxydeoxycorticosterone (18-hydroxy-DOC) was stimulated by ACTH when it was administered at rates between 5 μu./min and 5 mu./min. Increasing the K+ ion concentration of the perfusate from 3·6 to 5·4 and 8·9 mmol/l stimulated the production of aldosterone, 18-hydroxycorticosterone and deoxycorticosterone, although not of corticosterone or 18-hydroxy-DOC. This preparation has been used to study further the mechanism of secretion of corticosterone and 18-hydroxy-DOC. Thus, production of these two steroids was measured at different perfusion flows, varying between 0·1 and 0·6 ml/min, with different levels of ACTH stimulation. Corticosterone production was significantly (P < 0·001) increased by increasing flows both under control conditions and when ACTH was administered at constant rates of 50 μu./min or 1 mu./min. Production of 18-hydroxy-DOC was not affected by flow either under control conditions or with 50 μu. ACTH/min. However, when ACTH was administered at 1 mu./min, 18-hydroxy-DOC production was also significantly (P < 0·001) increased by flow. The results are consistent with those obtained in previous in-vitro studies and have been interpreted as suggesting that the main mechanism of corticosterone secretion is simple diffusion. In contrast, 18-hydroxy-DOC secretion, at least at sub-maximal levels of stimulation, appears to require a more complex process.

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