scholarly journals Time-dependent effects of starvation on pituitary, hypothalamic and serum prolactin levels in rats: Comparison to the galanin expression pattern

2016 ◽  
Vol 68 (1) ◽  
pp. 117-123
Author(s):  
Predrag Vujovic ◽  
Iva Lakic ◽  
Nebojsa Jasnic ◽  
Tanja Jevdjovic ◽  
Sinisa Ðurasevic ◽  
...  
Keyword(s):  
Energy Homeostasis ◽  
Metabolic Response ◽  
Expression Patterns ◽  
Male Rats ◽  
Serum Prolactin ◽  
Dark Phase ◽  
Ad Libitum ◽  
Pituitary Prolactin ◽  
Circulating Levels ◽  
Hypothalamic Level

Given that both prolactin and galanin take part in the regulation of energy homeostasis and that galanin is localized within lactotrophs, this study was aimed at comparing the pituitary expression patterns of prolactin and galanin during different phases of metabolic response to starvation in adult Wistar male rats. Food was removed at the onset of the dark phase (6:00 pm) and the animals were deprived for 6, 12, 24 and 48 h. Each of the starved groups (n=6) was killed simultaneously with a group of ad libitum-fed rats (n=6), and the intrapituitary levels of prolactin and galanin were examined. Galanin expression in the hypothalamus and the circulating levels of prolactin were also assessed. Starvation induced a rise in the intrapituitary prolactin level (p<0.001), whereas the opposite trend was detected in the serum (p<0.05). The galanin pituitary level was initially increased (6, 12 h) (p<0.05), but as starvation progressed, it first reached (at 24 h) and ultimately fell below the level recorded in the ad libitum rats (at 48 h) (p<0.05). Both prolactin and galanin were elevated in the hypothalamus after 24- and 48-h starvation. The results show that the starvation-induced increase in the pituitary prolactin expression did not lead to the rise in prolactin circulating levels, but rather resulted in the elevation of the prolactin hypothalamic content. Furthermore, the results suggest that under the circumstances of disturbed energy homeostasis, galanin might be responsible for the augmented prolactin production, initially at the pituitary and subsequently at the hypothalamic level.

scholarly journals Reverse Feeding Suppresses the Activity of the GH Axis in Rats and Induces a Preobesogenic State

Endocrinology ◽  
2011 ◽  
Vol 152 (3) ◽  
pp. 869-882 ◽  
Author(s):  
Camilla A.-M. Glad ◽  
Edward E. J. Kitchen ◽  
Gemma C. Russ ◽  
Sophie M. Harris ◽  
Jeffrey S. Davies ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Phase Inversion ◽  
Fatty Acid Synthase ◽  
Uncoupling Protein ◽  
Expression Patterns ◽  
Pulse Height ◽  
Male Rats ◽  
Dark Phase ◽  
Peroxisome Proliferator ◽  
Gh Secretion

Reversed feeding (RF) is known to disrupt hormone rhythmicity and metabolism. Although these effects may be mediated in part by phase inversion of glucocorticoid secretion, the precise mechanism is incompletely characterized. In this study, we demonstrate that acute nocturnal food deprivation in male rats suppressed the amplitude of spontaneous GH secretion during the dark phase by 62% (P &lt; 0.001), without affecting baseline secretion. Prolonged RF, which reduced pituitary weight (by 22%; P &lt; 0.05), also suppressed GH pulse height sufficiently to reduce skeletal growth (by 4–5%; P &lt; 0.01) and terminal liver weight (by 11%; P &lt; 0.001). Despite this suppression of the GH axis, proportionate adiposity was not elevated, probably due to the accompanying 16% reduction in cumulative food intake (P &lt; 0.01). We demonstrate that RF also resulted in phase inversion of core clock gene expression in liver, abdominal white adipose tissue (WAT) and skeletal muscle, without affecting their expression patterns in the suprachiasmatic nucleus. In addition, RF resulted in phase inversion of hepatic peroxisome proliferator-activated receptor γ2 mRNA expression, a 3- to 5-fold elevation in fatty acid synthase mRNA in WAT in both light- and dark-phase samples (P &lt; 0.01) and an elevation in muscle uncoupling protein 3 mRNA expression at the beginning of the light phase (P &lt; 0.01). Consumption of a high-fat diet increased inguinal (by 36%; P &lt; 0.05) and retroperitoneal WAT weight (by 72%; P &lt; 0.01) only in RF-maintained rats, doubling the efficiency of lipid accumulation (P &lt; 0.05). Thus, RF not only desynchronizes central and peripheral circadian clocks, and suppresses nocturnal GH secretion, but induces a preobesogenic state.

The effect of epitestosterone on gonadotrophin synthesis and secretion

1994 ◽  
Vol 143 (2) ◽  
pp. 353-358 ◽  
Author(s):  
O Lapcik ◽  
A Perheentupa ◽  
M Bicikova ◽  
I Huhtaniemi ◽  
R Hampl ◽  
...  
Keyword(s):  
Significant Negative Correlation ◽  
Inhibitory Effect ◽  
Male Rats ◽  
Mrna Levels ◽  
Α Subunit ◽  
Direct Inhibitory Effect ◽  
Testosterone Effect ◽  
Dose Dependent ◽  
Circulating Levels ◽  
Hypothalamic Level

Abstract The effects of 3-week treatment with increasing doses of epitestosterone (ET) on gonadotrophin gene expression and secretion, on testosterone and 5α-dihydrotestosterone (DHT) levels, and on the weight of testes and prostates, were studied in intact adult male rats. The hormones were delivered by means of silastic capsules of different lengths filled with the steroid. One group of rats received testosterone (T) instead of ET, to compare the results with previous studies concerning the testosterone effect. The controls were given capsules with glucose only. Treatment with ET, as well as with T, significantly reduced the weights of prostates. When the data from ET-treated rats and controls were combined, a significant negative correlation (P<0·001) was found between the weight of prostates and serum ET. T, in contrast to ET, also decreased significantly the weights of testes. ET treatment caused a significant reduction of serum T levels but only an insignificant decline of DHT levels, independent of the dose. Serum and pituitary (p) luteinizing hormone (LH) levels in the ET-treated rats did not change. Pituitary mRNA contents for the βLH subunit (βLH-mRNA) showed a dose-dependent significant increase, up to 170% (P<0·01), with ET treatment. pFSH decreased with the lowest ET (2 cm) dose (P<0·05), but no change was observed with the other doses. The mRNA for the common α-subunit also increased with the ET load. In conclusion, ET acts at several sites in the regulation of gonadotrophin formation and release. It enhances the steady-state mRNA levels of both gonadotrophins in the pituitary. At the same time, ET may act directly in the pituitary by inhibition of post-transcriptional events in LH synthesis. A direct inhibitory effect of ET at the hypothalamic level is also possible. The circulating levels of both gonadotrophins are thus the result of these composite effects. Journal of Endocrinology (1994) 143, 353–358

Time-restricted feeding entrains daily rhythms of energy metabolism in mice

2006 ◽  
Vol 290 (5) ◽  
pp. R1276-R1283 ◽  
Author(s):  
Yoko Satoh ◽  
Hiroshi Kawai ◽  
Naomi Kudo ◽  
Yoichi Kawashima ◽  
Atsushi Mitsumoto
Keyword(s):  
Energy Metabolism ◽  
Clock Genes ◽  
Expression Patterns ◽  
Daily Rhythm ◽  
Dark Phase ◽  
Restricted Feeding ◽  
Daily Rhythms ◽  
Peripheral Tissues ◽  
Temperature Rhythm ◽  
Ad Libitum

Energy metabolism, oxygen consumption rate (V̇o2), and respiratory quotient (RQ) in mice were monitored continuously throughout 12:12-h light-dark cycles before, during, and after time-restricted feeding (RF). Mice fed ad libitum showed robust daily rhythms in both parameters: high during the dark phase and low during the light phase. The daily profile of energy metabolism in mice under daytime-only feeding was reversed at the beginning of the first fasting night. A few days after daytime-only feeding began, RF also reversed the circadian core body temperature rhythm. Moreover, RF for 6 consecutive days shifted the phases of circadian expression patterns of clock genes in liver significantly by 8–10 h. When mice were fed a high-fat (HF) diet ad libitum, the daily rhythm of RQ dampened day by day and disappeared on the sixth day of RF, whereas V̇o2 showed a robust daily rhythm. Mice fed HF only in the daytime had reversed V̇o2 and RQ rhythms. Similarly, mice fed HF only in the daytime significantly phase shifted the clock gene expression in liver, whereas ad libitum feeding with HF had no significant effect on the expression phases of liver clock genes. These results suggested that V̇o2 is a sensitive indicator of entrainment in the mouse liver. Moreover, physiologically, it can be determined without any surgery or constraint. On the basis of these results, we hypothesize that a change in the daily V̇o2 rhythm, independent of the energy source, might drive phase shifts of circadian oscillators in peripheral tissues, at least in the liver.

Response to pinealectomy and blinding in vitellogenic female frogs (Rana perezi) subjected to high temperature in autumn

1990 ◽  
Vol 68 (1) ◽  
pp. 94-98 ◽  
Author(s):  
A. L. Alonso-Gómez ◽  
M. Tejera ◽  
M. Alonso-Bedate ◽  
M. J. Delgado
Keyword(s):  
High Temperature ◽  
Lipid Content ◽  
Metabolic Response ◽  
Natural Habitat ◽  
Ovarian Activity ◽  
Dark Phase ◽  
Pineal Complex ◽  
Fat Bodies ◽  
Circulating Levels ◽  
Rana Perezi

The present experiments were carried out to investigate the effects of pinealectomy and bilateral enucleation on the ovarian activity in Rana perezi frogs maintained in 12-h light – 12-h dark photoperiod and 20 ± 1 °C during the vitellogenetic growth in late autumn. These environmental conditions, mainly temperature, induce a gonadal and metabolic response similar to that observed in the natural habitat in summer: a marked ovarian follicular regression, a depletion of the energetic resources from fat bodies and liver, and a minimum in oestradiol circulating levels. This response is partially blocked by pinealectomy and blinding. Protein phosphorus, as an index of vitellogenic proteins, and total ovary lipid content were significantly higher in pinealectomized and blinded frogs with respect to sham-operated animals. Likewise, oestradiol concentrations showed a significant increase during the dark phase of the daily photocycle in pinealectomized and blinded animals. From our results, we can suggest that the arrest of vitellogenesis, the depletion of energetic resources, and the regulation of oestradiol levels induced by the high temperature in Rana perezi frogs can be influenced, at least in part, by the pineal complex and lateral eyes.Key words: pinealectomy, blinding, vitellogenesis, frog, temperature.

DNA SYNTHESIS AND DEPLETION OF PROLACTIN IN THE PITUITARY GLAND OF THE MALE RAT

1978 ◽  
Vol 77 (1) ◽  
pp. 129-136 ◽  
Author(s):  
H. M. LLOYD ◽  
J. M. JACOBI ◽  
J. D. MEARES
Keyword(s):  
Growth Hormone ◽  
Dna Synthesis ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Prolactin Secretion ◽  
Male Rats ◽  
Male Rat ◽  
Serum Prolactin ◽  
Inhibitory Effects ◽  
Pituitary Prolactin

Haloperidol, bromocriptine and diethylstilboestrol dipropionate were given in various régimes to male rats to determine their effects on pituitary DNA synthesis, prolactin secretion and growth hormone secretion. Haloperidol increased serum prolactin but did not stimulate pituitary DNA synthesis or reduce pituitary prolactin concentrations. Haloperidol potentiated the effects of oestrogen on serum prolactin and on pituitary DNA synthesis; pituitary prolactin concentrations were greatly reduced, and growth hormone secretion was slightly inhibited. The inhibitory effects of bromocriptine in oestrogen-stimulated rats were demonstrated by smaller pituitary weights and decreased DNA synthesis; serum prolactin levels were lowered and pituitary prolactin concentrations were increased. Haloperidol, given to rats treated with oestrogen and bromocriptine, reversed the inhibitory effects of bromocriptine on DNA synthesis and serum prolactin; pituitary prolactin concentrations fell to well below normal. The results suggest that the haloperidol potentiation of oestrogeninduced pituitary DNA synthesis may depend upon stimulation of prolactin secretion together with reduction of intracellular prolactin levels.

scholarly journals A Calorically Restricted High-fat Diet Reverses High-fat Diet-induced Injurious Effects on Health and Gene Expression in Rats

2019 ◽  
Author(s):  
Yuqing Wu ◽  
Yue Guan ◽  
Fan Ling ◽  
Qiushuang Zhu ◽  
Dandan Zhang ◽  
...  
Keyword(s):  
Gene Expression ◽  
High Fat Diet ◽  
Metabolic Diseases ◽  
Expression Patterns ◽  
Serum Levels ◽  
Male Rats ◽  
Gene Expression Patterns ◽  
High Fat ◽  
Ad Libitum ◽  
Group Serum

Abstract Background: A High-fat diet has been reported to produce excess lipid accumulation and increase inflammatory factors and oxidative stress in various metabolic diseases. Caloric restriction (CR) is one of the most valuable tools in reducing inflammation, enhancing anti-oxidative activity and ameliorating various metabolic diseases. However, excess CR may restrain growth, development and normal physiological processes. Our study was conducted to investigate the effects of a high-fat diet containing the same number of calories as a basic diet on the health and gene expression patterns of rats.Methods: 30 Wistar male rats were randomly devided into a normal control (NC) group, an equicaloric high-fat (EHF) group as the NC group, and a high-fat (HF) ad libitum group. Food consumption and body weight were recorded once a week. Blood biochemistical and genomic assessments of the liver were carried out after intervention for 20 weeks. Results: Compared with the NC group, serum triglycerides (TG), total cholesterol (TCHO), low-density lipoprotein cholesterol (LDL-C), aspartate aminotransferase (AST) and andalanine aminotransferase (ALT) levels were significantly increased in the HF group, and the serum levels of interleukin- 6 (IL-6), reactive oxygen species (ROS) and glutathione (GSH) were significantly decreased in the HF group. Compared with the HF group, serum TG,TCHO,LDL-C, AST, ALT, IL-6, ROS levels were significantly decreased in the EHF group, and the serum levels of GSH and superoxide dismutase (SOD) were also significantly increased. Histological studies showed decreased macrovesicular steatosis, inflammatory cell infiltration and structural damagein EHF group compared to the HF group. In addition, transcription analysis revealed that an EHF led tochanges in gene expression, including a reduction inToll-like receptor 4 (TRL4),which inhibited NF-kappa B signaling pathway and upregulatedglutathione S-transterases (GSTs) to increase antiocidative activity.Conclusions: an EHF restored deleterious changes in the health and gene expression patterns induced by a high-fat diet ad libitum in rats via reduced inflammation and increased antioxidative activity.

DEVELOPMENT OF STRESS-INDUCED PITUITARY PROLACTIN AND TSH RELEASE IN MALE RATS

1977 ◽  
Vol 85 (4) ◽  
pp. 729-735 ◽  
Author(s):  
M. Fenske ◽  
W. Wuttke
Keyword(s):  
Elevated Serum ◽  
Stress Factors ◽  
Male Rats ◽  
Serum Prolactin ◽  
Prolactin Release ◽  
Basal Serum ◽  
Normal Environment ◽  
Pituitary Prolactin ◽  
Serum Tsh ◽  
Tsh Levels

ABSTRACT Blood was collected from male rats of various ages under control conditions and after introduction of two stress factors. All animals were sacrificed between 15.00 and 16.00 h. Serum prolactin levels in immature male rats were found to be very low between birth and day 15 after birth. Neither exposure to a new environment, for example removal from the animal rooms for the duration of 10 min, nor exposure to concentrated ether vapour resulted in increased serum prolactin levels. Between day 20 and 35 basal serum prolactin levels were increased, they then fell at adult values. During this period of increasing serum prolactin levels pituitary prolactin release became stress-susceptable; i. e. elevated serum prolactin levels were observed after introduction of stress factors as in adult male rats. Serum TSH levels were found to be high between birth and day 10. Low TSH levels measured between day 15 and 40 and adult values were detected after day 40. Neither ether nor removal of the animals from their normal environment changed serum TSH levels at any age tested. These results indicate that the hypothalamo-pituitary in immature rats reacts in a similar way as that in adult animals from day 16–20 onwards. Serum TSH levels in these animals, however, are reduced, indicating that an increase in serum TSH is not necessary for normal processes of maturation.

EFFECTS OF TESTOSTERONE ON GONADOTROPHIN RESPONSES TO SYNTHETIC LH AND FSH RELEASING HORMONE (LRH) IN NORMAL MEN

1976 ◽  
Vol 83 (4) ◽  
pp. 692-699 ◽  
Author(s):  
C. Robyn ◽  
M. L'Hermite ◽  
R. Leclercq ◽  
G. Copinschi
Keyword(s):  
Intramuscular Injection ◽  
Serum Prolactin ◽  
Reserve Capacity ◽  
Intravenous Injections ◽  
Adult Men ◽  
Gonadotrophin Secretion ◽  
Normal Men ◽  
Lh Secretion ◽  
Circulating Levels ◽  
Hypothalamic Level

ABSTRACT LRH tests were performed in 6 adult men with intravenous injections of 25 μg, before and one week after an intramuscular injection of 250 mg testosterone oenanthate (Testoviron Depot®). One week after intramuscular injection of Testoviron the tonic secretion of LH was completely suppressed, but the reactivity or the reserve capacity of LH secretion, as tested by LRH, remained unchanged. In contrast, the tonic secretion of FSH and the reactivity of FSH secretion to LRH were both partly suppressed. Three months after the Testoviron injection, the basal levels of LH were still significantly lower than the control values, but the basal levels of FSH were identical to the control values. These data indicate that, in man, the feedback action of testosterone on gonadotrophin secretion could be exerted, at least for LH, at the hypothalamic level rather than at the pituitary level. No significant effects of LRH were noted on the circulating levels of growth hormone and sugar. There was a distinct rise in serum prolactin, which was occasionally significant, within 30 min after LRH injection; this is considered to be without physiological significance.

scholarly journals Importance of Adult Dmbx1 in Long-Lasting Orexigenic Effect of Agouti-Related Peptide

Endocrinology ◽  
2016 ◽  
Vol 157 (1) ◽  
pp. 245-257 ◽  
Author(s):  
Seiichiro Hirono ◽  
Eun Young Lee ◽  
Shunsuke Kuribayashi ◽  
Takahiro Fukuda ◽  
Naokatsu Saeki ◽  
...  
Keyword(s):  
Mouse Strain ◽  
Energy Homeostasis ◽  
Expression Patterns ◽  
Critical Role ◽  
Fetal Brain ◽  
Cre Recombinase ◽  
Calcitonin Gene Related Peptide ◽  
Adult Brain ◽  
Related Peptide ◽  
Calcitonin Gene

Abstract Dmbx1 is a brain-specific homeodomain transcription factor expressed primarily during embryogenesis, and its systemic disruption (Dmbx1−/−) in the ICR mouse strain resulted in leanness associated with impaired long-lasting orexigenic effect of agouti-related peptide (AgRP). Because spatial and temporal expression patterns of Dmbx1 change dramatically during embryogenesis, it remains unknown when and where Dmbx1 plays a critical role in energy homeostasis. In the present study, the physiological roles of Dmbx1 were examined by its conditional disruption (Dmbx1loxP/loxP) in the C57BL/6 mouse strain. Although Dmbx1 disruption in fetal brain resulted in neonatal lethality, its disruption by synapsin promoter-driven Cre recombinase, which eliminated Dmbx1 expression postnatally, exempted the mice (Syn-Cre;Dmbx1loxP/loxP mice) from lethality. Syn-Cre;Dmbx1loxP/loxP mice show mild leanness and impaired long-lasting orexigenic action of AgRP, demonstrating the physiological relevance of Dmbx1 in the adult. Visualization of Dmbx1-expressing neurons in adult brain using the mice harboring tamoxifen-inducible Cre recombinase in the Dmbx1 locus (Dmbx1CreERT2/+ mice) revealed Dmbx1 expression in small numbers of neurons in restricted regions, including the lateral parabrachial nucleus (LPB). Notably, c-Fos expression in LPB was increased at 48 hours after AgRP administration in Dmbx1loxP/loxP mice but not in Syn-Cre;Dmbx1loxP/loxP mice. These c-Fos-positive neurons in LPB did not coincide with neurons expressing Dmbx1 or melanocortin 4 receptor but did coincide with those expressing calcitonin gene-related peptide. Accordingly, Dmbx1 in the adult LPB is required for the long-lasting orexigenic effect of AgRP via the neural circuitry involving calcitonin gene-related peptide neurons.

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