Effects of ageing and exogenous melatonin on pituitary responsiveness to GnRH in rats

Reproduction ◽  
2000 ◽  
pp. 151-156 ◽  
Author(s):  
E Diaz ◽  
D Pazo ◽  
AI Esquifino ◽  
B Diaz

The effect of age and melatonin on the activity of the neuroendocrine reproductive system was studied in young cyclic (3-5 months-old), and old acyclic (23-25 month-old) female rats. Pituitary responsiveness to a bolus of GnRH (50 ng per 100 g body weight) was assessed at both reproductive stages in control and melatonin-treated (150 micrograms melatonin per 100 g body weight each day for 1 month) groups. After this experiment, female rats were treated for another month to study the influence of ageing and melatonin on the reproductive axis. Plasma LH, FSH, prolactin, oestradiol and progesterone were measured. A positive LH response to GnRH was observed in both control groups (cyclic and acyclic). However, a response of greater magnitude was observed in old acyclic rats. Melatonin treatment reduced this increased response in acyclic rats and produced a pituitary responsiveness similar to that of young cyclic rats. FSH secretion was independent of GnRH administration in all groups, indicating desynchronization between LH and FSH secretion in response to GnRH in young animals and during senescence. No effect on prolactin was observed. Significantly higher LH (3009.11 +/- 1275.08 pg ml(-1); P < 0.05) and FSH concentrations (5879.28 +/- 1631.68 pg ml(-1); P < 0.01) were seen in acyclic control rats. After melatonin treatment, LH (811.11 +/- 89.71 pg ml(-1)) and FSH concentrations (2070 +/- 301.62 pg ml(-1)) decreased to amounts similar to those observed in young cyclic rats. However, plasma concentrations of oestradiol and progesterone were not reduced. In conclusion, the results of the present study indicate that, during ageing, the effect of melatonin is exerted primarily at the hypothalamo-pituitary axis rather than on the ovary. Melatonin restored the basal concentrations of pituitary hormones and pituitary responsiveness to similar values to those observed in young rats.

2017 ◽  
pp. 507-518 ◽  
Author(s):  
K. A. A. MAJRASHI ◽  
I. A. H. BARAKAT ◽  
A. R. AL-HIMAIDI ◽  
K. G. ADHAM

Light is an important environmental factor that controls the regulation of physiological functions of organisms. Melatonin is considered as one of the major hormones that play an important role in protecting body from many harmful effects and acts as a powerful anti-oxidant source to controlling the levels of antioxidant enzymes within the body. The main objectives of this work were to study the effect of 1) photoperiod changes and 2) exogenous melatonin hormone treatment on the sperm properties, body and testis weight, embryo characteristics, and concentration level of melatonin and testosterone in treated rat serum. This study has been conducted using thirty-six male rats and one hundred and twenty female rats. Animals were divided into six groups, each group containing six males and twenty female rats. Our results showed a significant influence of photoperiod changes on the melatonin and testosterone hormones concentration in rats’ serum, body weight only, while the other characteristics not affected. As for the effect of melatonin it has been found that the movement of sperm in GIII and IV, as well as embryos absorbed and newborns weight traits has been significantly affected, while the rest of the properties were not significantly affected by melatonin treatment.


Author(s):  
Shakta Mani Satyam ◽  
Laxminarayana Kurady Bairy ◽  
Vasudha Devi

Objective: The objective of this study was to investigate the influence of gender and obesity on analgesic modulation of tramadol in Wistar rats.Methods: This study was carried out in two sets of experiments. In Set I experiment - 48 rats (body weight ≤150 g), 24 each male and female rats were randomly divided into two groups (n=6/group) (Group I - Control; 0.9% NaCl; 1 ml/kg/day i.p. and Group II - Tramadol 10 mg/kg/day i.p.) for each nociception model - plantar test and acetic acid-induced writhing test. The treatment duration was of 5 days. On the last day of treatment (i.e., on the 5th day), paw withdrawal latency (PWL) was assessed using plantar test, and writhing movements were observed following administration of 0.8% acetic acid; 10 ml/kg i.p. Set II experiment was repeated like Set I experiment among rest 48 high-fat diet-fed rats (body weight ≥300 g).Results: For both males and females, PWL was significantly decreased (p<0.05) in obese control groups compared to lean control groups. A number of writhing movements were significantly increased (p<0.01 for males and p<0.001 for females) in obese control groups compared to lean control groups. In tramadol-treated obese rats, PWL was significantly decreased (p<0.01 for males and p<0.05 for females), and number of writhing movements were significantly increased (p<0.01 for both males and females) in comparison with the tramadol-treated lean rats.Conclusion: The present study revealed that obese female rats experience more pain sensation to noxious stimuli compared to lean male rats and also the analgesic effect of tramadol is more pronounced in lean male rats compared to obese female rats.


2018 ◽  
Vol 37 (10) ◽  
pp. 1069-1079 ◽  
Author(s):  
V Leso ◽  
L Fontana ◽  
A Marinaccio ◽  
K Leopold ◽  
C Fanali ◽  
...  

The widespread industrial application of nanomaterials (NMs) has dramatically increased the likelihood of environmental and occupational exposure of humans to such xenobiotics. This issue, together with the increasing public health interest in understanding the effects of chemicals on endocrine system, encouraged to investigate the disruptive potential of NMs on the endocrine function. Therefore, the aim of this study was to evaluate the effects of palladium nanoparticles (Pd-NPs) on the female reproductive system of Wistar rats, intravenously exposed to different doses (0.12, 1.2, and 12 µg/kg), through the assessment of possible quantitative changes in the serum concentrations of several sex hormones. Our results demonstrated that the highest exposure doses significantly reduced the estradiol and testosterone concentrations, while increased the luteinizing hormone levels in treated animals compared to controls. Such alterations are indicative for an abnormal reproductive axis function. However, further investigations are needed to clarify the role of the different NP physicochemical properties in determining such effects, and possible underlining molecular mechanisms, as well as their relevance for the development of diseases in the female reproductive system. Overall, this may be helpful to define accurate risk assessment and management strategies to protect the health of the general and occupational populations exposed to Pd-NPs.


2018 ◽  
Vol 12 (2) ◽  
pp. 110-116
Author(s):  
Indah Maghfirah ◽  
Muhammad Jalaluddin ◽  
Dian Masyitha ◽  
Mustafa Sabri ◽  
Fadli A Gani ◽  
...  

The aim of this research was to identify the effect of sipatah-patah (Cissus quadrangularis Salisb) leaf extract on mandible density of ovariectomized rats (Rattus norvegicus). The samples were 12 female rats which were divided into 4 treatment groups with 3 replications. K0 consisted of ovariectomized rats without Cissus quadrangularis Salisb exstract, wheares K1, K2 and K3 consisted of ovariectomized rats  and were given Sipatah-patah extract with 500mg/kg body weight, 700/mg/kg body weight and 900mg/kg body weight for 30 days. On 31st day, rats were euthanized with cloroform and mandible bones were collected for histological preparation. Parameters observed were bone structures (osteosit, osteoblast, osteoclast and trabekula). The results showed that in K0 group, bone density was decreased and became thinner, osteoclast cells were found on trabekula, and low density of active and passive osteoblast were also detected. The treatment group (K1 and K2) showed an improvement stucture of trabekula,where the amount of osteoclast were lower than K0, as well as the amount of active osteoblast, although a lot of passive osteoblast were still found. The treatment group (K3) showed an improvement as the most dense trabekula structure with large amount of active osteoblast cell density without the existance of osteoclast compared to other grups. In this research, it would be concluded that the adding sipatah-patah extract with a dose of 900 mg/kb body weight showed a higher number of active osteoblasts and trabekula density compared to the control groups, K1, and K2 on ovariectomized mandible bone rats


2021 ◽  
Vol 4 (1) ◽  
pp. 99-114
Author(s):  
Janaína B Garcia ◽  
Fernanda G Do Amaral ◽  
Daniela C Buonfiglio ◽  
Rafaela FA Vendrame ◽  
Patrícia L Alves ◽  
...  

The pineal gland synthesizes melatonin exclusively at night, which gives melatonin the characteristic of a temporal synchronizer of the physiological systems. Melatonin is a regulator of insulin activities centrally and also peripherally and its synthesis is reduced in diabetes.  Since monosodium glutamate (MSG) is often used to induce the type 2 diabetic and metabolic syndrome in animal models, the purpose of this work is to evaluate the potential effects of MSG given to neonates on the pineal melatonin synthesis in different aged male and female rats. Wistar rats were subcutaneously injected with MSG (4mg/g/day) or saline solution (0.9%) from the second to eighth post-natal day. The circadian profiles both melatonin levels and AANAT activity were monitored at different ages. Body weight, naso-anal length, adipose tissues weight, GTT, ITT and serum insulin levels were also evaluated. Typical obesity with the neonatal MSG treatment was observed, indicated by a great increase in adipose depots without a concurrent increase in body weight. MSG treatment did not cause hyperglycemia or glucose intolerance, but induced insulin resistance. An increase of melatonin synthesis at ZT 15 with phase advance was observed in in some animals. The AANAT activity was positively parallel to the melatonin circadian profile. It seems that MSG causes hypothalamic obesity which may increase AANAT activity and melatonin production in pineal gland. These effects were not temporally correlated with insulin resistance and hyperinsulinemia indicating the hypothalamic lesions, particularly in arcuate nucleus induced by MSG in early age, as the principal cause of the increase in melatonin production.


1972 ◽  
Vol 70 (1) ◽  
pp. 167-174 ◽  
Author(s):  
Artur Ber

ABSTRACT Hypophysectomy was performed at the same time as ovariectomy in 19 rats aged 6 weeks; in addition a fragment of the animal's own ovary was implanted into the greater omentum. The graft took but there was complete cessation of the growth of the implant and a decrease in body and uterine weights as compared to 15 ovariectomized controls of the same age killed after one month. This shows that the pituitary is indispensable for the growth of ovarian implants but not for their take. In 84 spayed rats aged 3 weeks with ovarian implants, methallibure (6 mg/day in a 0.2% solution of Tween 20) was given by gavage during one month. Some of them were treated with PMSG (20 IU/day), HCG (20 IU/day) or with oestradiol benzoate (0.05 mg/day) only or in combinations. As controls, there were 74 spayed rats with ovarian implants, seven of which received Tween 20, and 67 were untreated. No differences were found between the two control groups. Methallibure alone caused arrest of the development of the implants and uteri and a decrease in body weight. In the methallibure treated animals HCG stimulated the growth of the implant which was, however, smaller than that in the controls, while PMSG restored the weight of the implant even above that of the control rats. Oestradiol benzoate caused a further diminution in the size of the implants but augmented considerably the influence of HCG on the implants. It had no effect on the weight of the implant in rats treated with PMSG. It is concluded that FSH is the principal implant growth-promoting factor and that oestrogens appear to act in two directions. They decrease the gonadotrophin output from the pituitary thus inhibiting the growth of the implants, but in the presence of gonadotrophins they act directly on the implants, promoting their development.


1971 ◽  
Vol 68 (3) ◽  
pp. 576-584 ◽  
Author(s):  
K. O. Nilsson ◽  
B. Hökfelt

ABSTRACT Metyrapone was administered either orally, 750 mg every four h, in a total of six doses, or intravenously 30 mg per kg body weight as a four h infusion. In three males with normal endocrine functions, metyrapone given orally or intravenously induced a fall in plasma testosterone and an elevation of androstenedione within 2–8 h. When metyrapone was administered to a patient given dexamethasone to suppress endogenous ACTH production, the androstenedione levels did not alter whereas the testosterone levels showed a slight, transient decrease. In two normal females metyrapone administration was followed by a marked increase in plasma androstenedione whereas testosterone showed only a minor, gradual increase. In one male patient with Addison's disease the basal plasma testosterone was normal whereas the level of androstenedione was low. Following metyrapone intravenously, there was a slight suppression of plasma testosterone but no change in the androstenedione concentration. In one patient with primary hypogonadism, two with secondary hypogonadism and two with Klinefelter's syndrome the plasma testosterone was low under basal conditions and did not change following metyrapone. Basal plasma androstenedione was within the range for normal males and increased markedly following metyrapone in all the cases.


2019 ◽  
Vol 20 (2) ◽  
pp. 60-69
Author(s):  
Gehad El-Sayed ◽  
Mohamed El-Diasty ◽  
Shaimaa Zayed

The use of Pediococcus (23×106 CFU/calf/day) orally in drinking milk once daily for one month in Holstein calves have highly significant effect on blood picture ,liver function tests, kidney function test ,blood electrolytes and body weight in cow calves. There were a significant increase in total erythrocytes count , hemoglobin content, packed cell volume, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, thrombocyte count, total leucocytes count, neutrophils counts, eosinophil, basophils, total protein and its fractions, level of alkaline phosphatase (ALP),level of sodium ,calcium ,phosphorus and body weight . On the other hand there were significant decrease in urea and potassium level in groups treated by Pediococcus compared to the control groups. Moreover there were a non-significant changes in lymphocytes, monocytes, creatinine, alanine transaminase (ALT), aspartate transaminase (AST), in the same groups compared to the control groups.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dominika Stygar ◽  
Tomasz Sawczyn ◽  
Agnieszka Dulska ◽  
Elżbieta Chełmecka ◽  
Łukasz Mielańczyk ◽  
...  

AbstractWe studied the long-term effect of ileal transposition (IT) metabolic surgery on the hepatokines: retinol-binding protein-4 (RBP4), α-2-HS-glycoprotein (aHSG/fetuin-A), and fibroblast growth factor 21 (FGF21), C-reactive protein (CRP) plasma levels, glucose metabolism, body weight, liver histology, as well as total lipids concentration in muscle, liver, and fat tissue of obese Zucker (Crl:ZUC(ORL)-Leprfa) rats. 14 adult males were randomly submitted either to IT or SHAM (control) surgery. Pre-operative hepatokines plasma levels were not significantly different in rats submitted to IT or SHAM protocol. Three months after the procedures the plasma levels of RBP4, aHSG, FGF21, and CRP were significantly lower in IT-operated animals when compared to SHAM-operated group. Three and 12 weeks after the IT and SHAM surgery, the AUCOGTT were significantly lower than AUCOGTT before the surgery. HOMA-IR was lower in rats after IT surgery in comparison to the SHAM-operated rats. Muscle and liver total lipids concentration was reduced after the IT procedure when compared to pre-IT conditions. IT had a significant reductive impact on the body weight in comparison to SHAM surgery in the 4th, 6th, 8th, and 10th week after the surgery. We conclude that IT reduces hepatokines’ plasma concentrations, muscle and liver total lipids concentration but not the inflammatory processes in the liver of Zucker (Crl:ZUC(ORL)-Leprfa) rats.


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