Effects of Gender, Gonadectomy and Sex Hormones on Growth and Plasma Cholesterol Level in Rats

Lee, Chong-Eon; Kang, Jungsuk; Kim, Kyu-Il

doi:10.1159/000152867

Cited by 14 publications

(13 citation statements)

References 28 publications

(22 reference statements)

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“…In the present study, we conducted two experiments to determine the effect of gender and gonadectomy on growth, feed efficiency and plasma cholesterol levels, using pigs as a model animal to confirm the findings of our previous study done with rats (Lee et al, 2008). …”

Section: Introductionsupporting

confidence: 77%

“…Our previous studies (Lee et al, 1999; Lee et al, 2008) showed a much higher plasma cholesterol level in female than in male rats when they were fed a hypercholesterolemic diet (CD). Naito et al (1995) proposed that the effect of sex hormones on lipid metabolism is not likely to account for the sex difference in cardiovascular disease.…”

Section: Introductionmentioning

confidence: 97%

“…Our recent study (Lee et al, 2008) demonstrated that a lower growth rate in female rats was due to estrogen, which induced secretion of the stress hormone cortisol. Similarly, other studies (Burgess & Handa, 1992; Lesniewska et al, 1990) also showed gender differences in cortisol secretion, indicating that estrogen elevates basal levels of cortisol, corticosterone and adrenocorticotropin, and their responses to various stimuli in rats.…”

Section: Introductionmentioning

confidence: 99%

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Effects of gender and gonadectomy on growth and plasma cholesterol levels in pigs

Lee

Kim

2009

Nutr Res Pract

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We conducted two studies to determine the effect of gender, gonadectomy (GDX) on growth and plasma cholesterol levels in pigs. In experiment 1, five sham-operated and five GDX female Landrace pigs (26 kg) were allowed to have free access to water and feed up to market weight (approximately 100 kg). Body weight and feed consumption were recorded biweekly, and daily body weight gain, daily feed intake and feed efficiency (gain/feed) were calculated during the feeding period. In experiment 2, 10 male (26 kg) and 10 female (26 kg) Landrace pigs were used; five male and five female pigs were assigned to sham-operated or GDX. Pigs were allowed to have free access to water and a diet without added cholesterol (Table 1) until they were 6 months old (male 104 and female 98 kg) and thereafter they were fed a hypercholesterolemic diet (Table 1) containing 0.5% cholesterol and 0.1% cholate for 10 days. GDX of female pigs increased average daily gain (P<0.05), compared with their sham-operated counterparts during the growing-finishing period, but had no effect (P>0.05) on feed efficiency. Plasma cholesterol levels in pigs fed a hypercholesterolemic diet for 10 days were much higher (P<0.05) in females than in males (161 vs 104 mg/100 mL plasma), and were increased by GDX only in male pigs. HDL-cholesterol/LDL+VLDL-cholesterol ratio appeared to be higher in males than in females, and was not influenced by GDX in either sex. Results suggested that the lower growth rate of female pigs than their male counterparts is attributable to the ovarian activity, and the lower plasma cholesterol level in male than in female pigs fed a hypercholesterolemic diet is due to the testicular activity.

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Section: Introductionsupporting

confidence: 77%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Effects of gender and gonadectomy on growth and plasma cholesterol levels in pigs

Lee

Kim

2009

Nutr Res Pract

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“…Several clinical and epidemiological studies have reported that serum testosterone levels are inversely correlated with total cholesterol and LDL cholesterol levels [9-11]. Moreover, animal studies have also demonstrated markedly increased serum cholesterol levels in testosterone-deficient male mice [12,13]. These findings indicate that testosterone serves an important role in regulating serum cholesterol metabolism.…”

Section: Introductionmentioning

confidence: 99%

Effect of testosterone deficiency on cholesterol metabolism in pigs fed a high-fat and high-cholesterol diet

et al. 2015

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BackgroundTestosterone deficiency is associated with increased serum cholesterol levels. However, how testosterone deficiency precisely affects cholesterol metabolism remains unclear. Therefore, in the current study, we examined the effect of testosterone deficiency on cholesterol metabolism and liver gene expression in pigs fed a high-fat and high-cholesterol (HFC) diet.MethodsSexually mature male miniature pigs (6–7 months old) were randomly divided into 3 groups as follows: intact male pigs fed an HFC diet (IM + HFC), castrated male pigs fed an HFC diet (CM + HFC), and castrated pigs with testosterone replacement fed an HFC diet (CM + HFC + T). Serum testosterone levels and lipid profiles were measured, and gene expression levels associated with hepatic cholesterol metabolism were determined. Furthermore, total hepatic cholesterol contents and the activities of enzymes mediating hepatic cholesterol metabolism were measured.ResultsSerum testosterone levels were significantly decreased in CM + HFC pigs, and testosterone replacement attenuated castration-induced testosterone deficiency. Castration significantly increased the serum levels of total cholesterol, low-density lipoprotein cholesterol and triglycerides, as well as hepatic lipid contents in pigs fed an HFC diet. Compared with IM + HFC and CM + HFC + T pigs, low-density lipoprotein receptor (LDLR) mRNA expression and protein levels were significantly decreased in the livers of CM + HFC pigs. In contrast, we found that compared with IM + HFC pigs, hepatic proprotein convertase subtilisin/kexin type 9 (PCSK9) mRNA and serum PCSK9 protein levels were significantly increased in CM + HFC pigs. Moreover, testosterone treatment reversed the increase in PCSK9 expression in CM + HFC pigs. However, neither castration nor testosterone replacement affected the expression of the other hepatic genes that were tested.ConclusionsThis study demonstrated that castration-induced testosterone deficiency caused severe hypercholesterolemia in pigs fed an HFC diet; furthermore, these effects could be reversed by testosterone replacement therapy. Altered hepatic PCSK9 and LDLR expression, resulting in reduced LDL-cholesterol clearance, may contribute to the increased serum cholesterol levels induced by testosterone deficiency and an HFC diet. These results deepen our understanding of the underlying molecular mechanisms that mediate the effects of testosterone deficiency on cholesterol metabolism.

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“…Clinical studies reported that testosterone levels inversely correlated with total cholesterol and LDL cholesterol levels [11][12][13] . In addition, animal studies demonstrated highly elevated cholesterol levels in testosterone-deficient male mice 14,15 . These findings suggested that testosterone serves a valuable role in regulating serum lipids.…”

Section: Introductionmentioning

confidence: 99%

Effects of Testosterone Replacement on Insulin Sensitivity, Blood Glucose, Serum Lipids and Vitamin D Concentration in a Rat Model of Andropause

Rezk¹

2017

IJCEMS

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Abstract:Background: Testosterone facilitates various metabolic processes in the bones, muscles, bone marrow, brain and immune system. Testosterone deficiency may contribute to cardiovascular diseases, central obesity and metabolic dysfunction. Aim: to investigate the effects of testosterone deficiency on blood glucose levels, insulin sensitivity, vitamin D, Homeostatic model assessment of insulin resistance (HOMA-IR), Homeostatic model assessment for beta function (HOMA-IR) and serum lipids in rat models of andropause. Methods, 48 male rats divided into 4 equal groups (n=12/group); a) Control (C) group. b) Orchiectomy (O) group underwent bilateral removal of the testicles. c) Orchiectomy and treated (O+T) group given daily IM testosterone replacement therapy for 7 days, d) Sham and treated (Sh+T) group in which sham operated rats were given the same daily dose of T as O+T group for 7 days. Results: we found that plasma glucose concentration increased significantly (P<0.001) in O group. This increase was corrected by testosterone injection in O+T group. In (Sh+T) group, there is a significant reduction in serum glucose (P<0.001). We also found that insulin level reduced significantly (P<0.001) in O group. This reduction in insulin level was corrected by testosterone. In (Sh+T) group, insulin level increased significantly. 25-OHVD3 was reduced significantly (P<0.05) in O group and increased significantly in O+T group. HOMA-IR level decreased significantly (P<0.001) and this reduction was corrected by Testosterone. HOMA-β reduced significantly (P<0.001) and this reduction was corrected by Testosterone in O+T group. In SH group, there is a marked increase in HOMA-β. We also found insignificant differences between the four groups in serum triglycerides. However, we found very highly significant differences in total cholesterol, LDL and VLDL between C group and O group and very highly significant differences between O+T group and Sh+T group in comparison with O group. We also found significant differences in serum HDL-c in (O) group in comparison with (C) group and between O+T and Sh+T groups in comparison with O group. In conclusion, we found significant reduction in 25-OH(VD), Testosterone, Insulin, HOMA-IR and HOMA-B and significant increase in glucose serum levels in O group and these changes were corrected by Testosterone injection in O+T group. We also found insignificant differences between the four groups in serum triglycerides. However, we found highly significant differences in total cholesterol, LDL, HDL-c and VLDL between C group and O group and very highly significant differences between O+T group and Sh+T group in comparison with O group.

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Effects of Gender, Gonadectomy and Sex Hormones on Growth and Plasma Cholesterol Level in Rats

Cited by 14 publications

References 28 publications

Effects of gender and gonadectomy on growth and plasma cholesterol levels in pigs

Effects of gender and gonadectomy on growth and plasma cholesterol levels in pigs

Effect of testosterone deficiency on cholesterol metabolism in pigs fed a high-fat and high-cholesterol diet

Effects of Testosterone Replacement on Insulin Sensitivity, Blood Glucose, Serum Lipids and Vitamin D Concentration in a Rat Model of Andropause

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