Differential orderliness of the GH release process in castrate male and female rats

1998 ◽  
Vol 274 (2) ◽  
pp. R437-R444 ◽  
Author(s):  
Evelien Gevers ◽  
Steve M. Pincus ◽  
Iain C. A. F. Robinson ◽  
Johannes D. Veldhuis
Keyword(s):  
Gnrh Agonist ◽  
Rank Order ◽  
Female Rats ◽  
Sex Steroid ◽  
Intact Male ◽  
Castrate Male ◽  
Male And Female ◽  
Releasing Hormone ◽  
Male And Female Rats ◽  
The Impact

Male- and female-specific modes of episodic growth hormone (GH) release are presumptively imposed by sex steroid hormones, and, although typically evident visually, are vividly distinguished quantitatively via a regularity statistic, approximate entropy (ApEn), in both the rat and human. GH secretory patterns may determine GH-stimulated growth and specific hepatic and muscle gene expression in the rat. Consequently, it is important to discern mechanisms that underlie their regulation. Here we have examined the impact of prepubertal gonadal suppression (at 4 wk of age) via surgical or pharmacological [gonadotropin-releasing hormone (GnRH) agonist] intervention on the regularity (ApEn) of GH release in male and female rats (at 10–11 wk of age) sampled at 10-min intervals for 10 h ( n = 60 points) during a lights-out (dark) period. We observed a graded hierarchy of mean disorderliness of GH release that was quantifiable by ApEn measures, with maximal to minimal disorderliness in the following rank order: intact female, GnRH agonist-treated female, ovariectomized female, orchidectomized male, GnRH agonist-treated male, and intact male. These observations suggest a continuum of sex steroid actions on the regularity of GH secretion and, by inference, on the interplay among GH-releasing hormone, somatostatin, and GH/insulin-like growth factor I negative feedback.

Estrogen and prothrombin synthesis: effect of estrogen on absorption of vitamin K1

1977 ◽  
Vol 232 (1) ◽  
pp. H12-H17 ◽  
Author(s):  
D. W. Jolly ◽  
C. Craig ◽  
T. E. Nelson
Keyword(s):  
Female Rats ◽  
Male Rats ◽  
Thoracic Duct Lymph ◽  
Albino Rats ◽  
Vitamin K1 ◽  
Intact Male ◽  
Deficient Diet ◽  
Castrate Male ◽  
Male And Female ◽  
Male And Female Rats

Intact male and female albino rats fed a vitamin K-deficient diet develop a plasma prothrombin-proconvertin deficiency. Male rats respond with a precipitous drop to approximately 20–30% of normal plasma levels within 2–5 days, whereas female rats respond at a slower rate. Ethynylestradiol, 5–10 mug/day, or castration, reduces the progressive decline of plasma prothrombin-proconvertin seen in nonsupplemented intact male rats. The response of castrate females differs little from the response of intact females. Ethynylestradiol, 5–10 mug/day, affects both castrate males and females similarly, limiting the prothrombin-proconvertin decrease to about 13% below control value after 14 days. Intestinal absorption of vitamin K1 measured in the thoracic duct lymph of pentobarbital-anesthetized castrate male and female rats was shown to increase significantly after estrogen treatment. Estrogen-treated castrate male and female rats absorbed 25.8 mug and 11.8 mug vitamin K1, respectively. Nontreated control castrate male and female rats absorbed 0.0 mug and 1.2 mug, respectively, during a 240-min collection period. Use of radioactive vitamin K1 in similar experiments confirmed these results. Estrogen-treated castrate males absorbed vitamin K1 at the rate of 30-40 mug/g lymph whereas nontreated control males absorbed only about 6 mug/g lymph.

scholarly journals Effects of new generation triptans – frovatriptan and almotriptan – on hemodynamic parameters in intact male and female rats

2020 ◽  
Vol 70 (2) ◽  
pp. 239-247
Author(s):  
Kremena Saracheva ◽  
Petar Hrischev ◽  
Liliya Vasileva ◽  
Mariyan Topolov ◽  
Julia Nikolova ◽  
...  
Keyword(s):  
Second Generation ◽  
Female Rats ◽  
Male Rats ◽  
Hemodynamic Parameters ◽  
Intact Male ◽  
Male And Female ◽  
Arterial Blood ◽  
Male And Female Rats ◽  
Male Wistar Rats ◽  
The Impact

AbstractThe introduction of the second generation triptans in clinical and experimental practice was a major progress in the pharmacotherapy of migraine. Frovatriptan is a second generation triptan with strong 5-HT1B/1D serotonergic agonism and low 5-HT1A/7 receptor affinity, while almotriptan possesses not only the typical 5-HT1B/1D receptor agonist activity, but shows an affinity to the 5-HT1F receptor. The aim of our study was to assess the impact of frovatriptan and almotriptan on hemodynamics in male and female rats. We used a non-invasive “tail-cuff” method to measure the arterial blood pressure. Female and male Wistar rats were treated separately with high and low dosages of frovatriptan and almotriptan. Male and female rats showed reduction in all hemodynamic parameters, but only male rats showed an increase in the heart rate. In general, we could say that both almotriptan and frovatriptan potentiate cardiovascular safety.

1,2-3H-TESTOSTERONE: DISTRIBUTION AND UPTAKE IN NEURAL AND GENITAL TISSUES OF INTACT MALE, CASTRATE MALE AND FEMALE RATS

1969 ◽  
Vol 61 (4) ◽  
pp. 629-640 ◽  
Author(s):  
S. K. Roy ◽  
K. R. Laumas
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Soluble Fraction ◽  
Anterior Pituitary Gland ◽  
Female Rats ◽  
Constant Infusion ◽  
Intact Male ◽  
Castrate Male ◽  
Male And Female ◽  
Male And Female Rats

ABSTRACT This report deals with a comparative study of the uptake of radioactivity in the genital, neural and other tissues of intact male, castrate male and female rats after constant infusion of radiochemically pure 1,2-3H-testosterone. Castration has been found to have a marked effect in enhancing the uptake of radioactivity in the different tissues particularly liver and kidney which have a metabolic and excretory role. Prostate and seminal vesicles, on the other hand, did not show any difference in uptake in intact and castrate rats. The uptake of testosterone and its metabolites in the prostate of intact animals was 3.46 × 10−9 m. In experiments on subcellular localization of radioactivity after constant infusion of 1,2-3H-testosterone, it was found that prostate and seminal vesicle had heavy localisation in the nuclear and 105 000 × g soluble fraction while the major localisation of radioactivity in the case of nontarget tissues like liver, intestine, muscle etc. was in the soluble fraction. Castration caused a higher uptake of radioactivity in the anterior pituitary gland, anterior and middle hypothalamus also, which could be explained on the basis of the negative feedback of the hormone. An interesting feature of the uptake of testosterone and its metabolites in the female rat was the high uptake in the anterior pituitary gland, and the various parts of the hypothalamus. These findings are discussed in light of information available on the action and feedback of sex hormones.

024 Quiescent Wakefulness: Characterising the Impact of Oxytocin on Sleep-Wake Behaviour in Male and Female Rats

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A11-A11
Author(s):  
Joel Raymond ◽  
Nicholas Everett ◽  
Anand Gururajan ◽  
Michael Bowen
Keyword(s):  
Rem Sleep ◽  
Sleep Onset ◽  
Conscious State ◽  
Positive Control ◽  
Female Rats ◽  
Male And Female ◽  
Routes Of Administration ◽  
Male And Female Rats ◽  
Competing Hypotheses ◽  
The Impact

Abstract Introduction Oxytocin is a versatile hypothalamic neuropeptide involved in diverse neurobehavioural processes. Since oxytocin can elicit anxiolytic and serenic effects, one could hypothesise that oxytocin should prime the brain for sleep and promote hypnogenesis. However, based on the social salience hypothesis—that oxytocin promotes prosocial behaviour and directs attention toward social stimuli—one could also posit that oxytocin should promote wakefulness. At present, little research has comprehensively characterised the effect of oxytocin on sleep-wake behaviour and no explanation to reconcile these two seemingly competing hypotheses has been proposed. Methods This study investigated the effects of oxytocin on sleep-wake outcomes using radiotelemetry-based polysomnography in adult male and female Wistar rats. Oxytocin was administered via the intraperitoneal (IP; 0.1, 0.3 and 1 mg/kg) and intranasal (IN; 0.06, 1, 3 mg/kg) routes. Caffeine (IP and IN; 10 mg/kg) was also administered as a wake-promoting positive control. Additionally, pre-treatment with the oxytocin receptor (OTR) antagonist L-368,899 (IP; 5 mg/kg) and vasopressin 1a receptor (V1aR) antagonist SR49059 (IP; 1 mg/kg) followed by oxytocin (IP; 1 mg/kg) was conducted to determine which receptor(s) mediated sleep-wake effects of oxytocin. Results In both male and female rats, IP oxytocin produced dose-dependent effects on sleep-wake behaviour. Specifically, oxytocin initially promoted quiescent wakefulness (a restful but conscious state) at the cost of reducing both active wakefulness and sleep. Throughout the 1.5-hour period post-administration, oxytocin delayed REM sleep onset and reduced the proportion of both NREM and REM sleep. Conversely, IN oxytocin did not significantly alter any sleep-wake parameters at any dose tested. Caffeine demonstrated wake-promoting effects under both the IP and IN routes of administration. The involvement of OTR and V1aR binding in oxytocin-induced effects on sleep-wake outcomes will be discussed. Conclusion These findings appear to reconcile the two competing hypotheses: in rats, IP oxytocin appears to promote a state of quiescent wakefulness—one of calm and rest, but also of conscious responsivity to environmental stimuli. IN oxytocin demonstrated little to no effect on sleep-wake behaviour, which is a crucial finding given the escalating use of IN oxytocin as a therapeutic for conditions with comorbid disordered sleep. Support (if any) None.

Dietary Soy Supplements Produce Opposite Effects on Anxiety in Intact Male and Female Rats in the Elevated Plus-Maze.

2005 ◽  
Vol 119 (2) ◽  
pp. 587-594 ◽  
Author(s):  
Heather B. Patisaul ◽  
Adele Blum ◽  
Jordan R. Luskin ◽  
Mark E. Wilson
Keyword(s):  
Elevated Plus Maze ◽  
Female Rats ◽  
Intact Male ◽  
Male And Female ◽  
Male And Female Rats ◽  
Plus Maze

scholarly journals Progesterone stimulates pancreatic cell proliferation in vivo

1999 ◽  
pp. 256-263 ◽  
Author(s):  
AG Nieuwenhuizen ◽  
GA Schuiling ◽  
SM Liem ◽  
H Moes ◽  
TR Koiter ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Pancreatic Islets ◽  
Pancreatic Tissue ◽  
Female Rats ◽  
Cytokeratin 20 ◽  
Intact Male ◽  
Pancreatic Cell ◽  
Male And Female ◽  
Progesterone Treatment ◽  
Male And Female Rats

Treatment of cyclic and pregnant rats with progesterone stimulates cell proliferation within the islets of Langerhans. It was investigated whether this effect of progesterone depends on sex and/or the presence of the gonads or the presence of oestradiol. For this purpose, Silastic tubes containing progesterone were inserted s.c. in intact and gonadectomized male and female rats, and in gonadectomized female rats treated with oestradiol. After 6 days of progesterone treatment, rats were infused for 24 h with 5-bromo-2'-deoxyuridine (BrdU) and dividing cells were identified in pancreatic sections by immunostaining for BrdU. Progesterone treatment increased islet-cell proliferation in intact male and female rats (P < 0.05), but not in gonadectomized male and female rats or in gonadectomized female rats supplemented with oestradiol. Furthermore, in intact male and female rats, progesterone treatment also stimulated cell proliferation in extra-islet pancreatic tissue (P < 0.05). Identification of the proliferating cells, by double-immunocytochemistry, revealed that progesterone treatment stimulated proliferation of both alpha and beta cells within the pancreatic islets. In extra-islet pancreatic tissue, progesterone treatment stimulated proliferation in both duct (cytokeratin 20-immunoreactive) and non-duct cells. Progesterone treatment did not increase the number of single glucagon or insulin-containing cells outside the pancreatic islets, nor that of cytokeratin 20/insulin double-positive cells, suggesting that progesterone treatment did not stimulate differentiation of duct cells into endocrine cells. Progesterone treatment did not affect insulin responses to an i.v. glucose load (0.5 g/kg body weight). It is concluded that progesterone stimulates pancreatic cell proliferation indirectly; gonadal factor(s), not identical to oestradiol, is (are) probably involved.

scholarly journals NONCLINICAL STUDY OF THE TOXICITY OF A NEW ANTICANCER DRUG ОRMUSTIN ON SMALL LABORATORY ANIMALS

2015 ◽  
Vol 14 (4) ◽  
pp. 65-72 ◽  
Author(s):  
V. A. Chaley ◽  
O. I. Konyaeva ◽  
N. P. Ermakova ◽  
A. A. Nikolina ◽  
V. M. Bukhman ◽  
...  
Keyword(s):  
Anticancer Drug ◽  
Intravenous Administration ◽  
Female Rats ◽  
Laboratory Animals ◽  
Small Laboratory ◽  
Male And Female ◽  
Male And Female Rats ◽  
The Impact ◽  
Hybrid Mice ◽  
Nonclinical Study

The paper presents the results of the study of «acute» toxicity and some results of the study of «subchronic» toxicity of Ormustin, a new anticancer drug belonging to nitrosourea class, in small laboratory animals. In the experiments the laboratory animals - hybrid mice (C57Bl/6J×DBA/2)F1 male and female and outbred male and female rats have been used. On the results of study has been obtained the calculated toxic doses of Ormustin at intravenous administration of the drug in mice and rats; has been given the preliminary assessment of the impact of Ormustin on organs and systems of rats at multiple intravenous administration.

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