Gender and Fat Metabolism During Exercise: A Review

1998 ◽  
Vol 23 (6) ◽  
pp. 570-582 ◽  
Author(s):  
Charlotte A. Tate ◽  
Robert W. Holtz
Keyword(s):  
Muscle Glycogen ◽  
Respiratory Exchange Ratio ◽  
Fat Metabolism ◽  
Mature Female ◽  
Submaximal Exercise ◽  
Female Rats ◽  
Male Rats ◽  
Cellular Mechanisms ◽  
Cellular Processes ◽  
Fat Utilization

We examined the evidence for greater fat utilization by women during exercise and the potential gender differences in specific cellular processes. Results from well-controlled studies show that, compared to men, women oxidize more fat during submaximal exercise, resulting in the relative sparing of muscle glycogen. Mature female rats use less muscle glycogen during running and can run longer than male counterparts. Circulating estrogen is critical to these observations, as shown by studies where male rats were treated with estrogen. Estrogen-treated male rats use less muscle glycogen during exercise and can run longer than untreated males. The cellular mechanisms and factors underlying these findings are unknown and certainly multifactorial. We offer some information that, unfortunately, does not lead to any natural conclusion. However, this area is certainly ripe for research. Key words: respiratory exchange ratio, fat metabolism, glycogen, estrogen, mitochondrion

Muscle metabolism during exercise in the heat in unacclimatized and acclimatized humans

1985 ◽  
Vol 59 (5) ◽  
pp. 1350-1354 ◽  
Author(s):  
D. S. King ◽  
D. L. Costill ◽  
W. J. Fink ◽  
M. Hargreaves ◽  
R. A. Fielding
Keyword(s):  
Muscle Glycogen ◽  
Respiratory Exchange Ratio ◽  
Muscle Metabolism ◽  
Submaximal Exercise ◽  
Intense Exercise ◽  
O2 Uptake ◽  
Heat Acclimatization ◽  
Fuel Selection ◽  
Muscle Ph ◽  
Male Subjects

The effect of heat acclimatization on aerobic exercise tolerance in the heat and on subsequent sprint exercise performance was investigated. Before (UN) and after (ACC) 8 days of heat acclimatization, 10 male subjects performed a heat-exercise test (HET) consisting of 6 h of intermittent submaximal [50% of the maximal O2 uptake] exercise in the heat (39.7 degrees C dB, 31.0% relative humidity). A 45-s maximal cycle ride was performed before (sprint 1) and after (sprint 2) each HET. Mean muscle glycogen use during the HET was lower following acclimatization [ACC = 28.6 +/- 6.4 (SE) and UN = 57.4 +/- 5.1 mmol/kg; P less than 0.05]. No differences were noted between the UN and ACC trials with respect to blood glucose, lactate (LA), or respiratory exchange ratio. During the UN trial only, total work output during sprint 2 was reduced compared with sprint 1 (24.01 +/- 0.80 vs. 21.56 +/- 1.18 kJ; P less than 0.05). This reduction in sprint performance was associated with an attenuated fall in muscle pH following sprint 2 (6.86 vs. 6.67, P less than 0.05) and a reduced accumulation of LA in the blood. These data indicate that heat acclimatization produced a shift in fuel selection during submaximal exercise in the heat. The observed sparing of muscle glycogen may be associated with the enhanced ability to perform highly intense exercise following prolonged exertion in the heat.

Change from beta- to alpha-adrenergic glycogenolysis induced by corticosteroids in female rat liver

1997 ◽  
Vol 273 (1) ◽  
pp. R153-R160
Author(s):  
M. Moriyama ◽  
Y. Nakanishi ◽  
S. Tsuyama ◽  
Y. Kannan ◽  
M. Ohta ◽  
...  
Keyword(s):  
Glucose Production ◽  
Plasma Corticosterone ◽  
Mature Female ◽  
Female Rats ◽  
Male Rats ◽  
Female Rat ◽  
Circadian Variations ◽  
Male And Female ◽  
Male And Female Rats ◽  
The Difference

The conversion of beta- to alpha-adrenergic glycogenolysis by corticosteroids was studied in perfused livers of mature female rats. Isoproterenol stimulated glucose production more effectively in female rats than in male rats, but the difference in its stimulatory effect disappeared in adrenalectomized (ADX) rats, whereas it remained in adrenodemedulated rats. When ADX female rats were treated with dexamethasone sulfate, alpha-responses increased and beta-responses decreased, depending on the concentration of dexamethasone sulfate. The treatment of female rats with 1.5 mg/kg dexamethasone sulfate changed the levels of the alpha- and beta-responses to those observed in male rats, and the changes were associated with changes in the number of receptors. Although periodicity of changes in plasma corticosterone levels was observed in both male and female rats, the extent of circadian variations was significantly lower in female rats during the estrous cycle than in male rats. The variations in plasma corticosterone levels and in both alpha- and beta-responses after ovariectomy approached those in male rats. The results suggest that the level of plasma corticosterone might play an important role in the regulation of the relative levels of alpha- and beta-adrenergic responses in female rats.

Cyclic and diurnal alterations in the response of luteinizing hormone and prolactin to prostaglandin E2 during the rat oestrous cycle

1984 ◽  
Vol 106 (1) ◽  
pp. 30-37 ◽  
Author(s):  
Lise Wogensen ◽  
Jørgen Warberg
Keyword(s):  
Luteinizing Hormone ◽  
Prostaglandin E2 ◽  
Lateral Ventricle ◽  
Mature Female ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Male Rats ◽  
Prostaglandin E ◽  
The Brain ◽  
Time Of Administration

Abstract. Two μg of prostaglandin E2 (PGE2) was infused into a lateral ventricle of the brain of female rats at 09.00 or 13.00 h on the different days of the oestrous cycle and the effect on luteinizing hormone (LH) and prolactin (Prl) release was determined. At 09.00 h PGE2 caused a pronounced release of LH in pro-oestrous, oestrous and metoestrous rats whereas the LH response in dioestrous rats was moderate. The secretion of Prl was only stimulated in rats from the pro-oestrous phase. When infused at 13.00 h PGE2 had a marked stimulatory effect on the release of LH in all groups of rats. The response was almost the same in oestrous, metoestrous and dioestrous rats but pro-oestrous rats a 2-fold higher LH response was observed. On each day of the oestrous cycle it was found that the LH-releasing activity of PGE2 was greater at 13.00 h than at 09.00 h. Thus, the overall greatest responsiveness of LH to PGE2 was noted at 13.00 h on pro-oestrus i.e. at a time which was prior to the onset of the spontaneous LH surge. At 13.00 h – as at 09.00 h – PGE2 was only capable of stimulating Prl release in pro-oestrous rats. Resembling the LH response it was found that PGE2-induced Prl release was greater at 13.00 h than at 09.00 h. In adult male rats the stimulatory effect of PGE2 on LH and Prl release was independent of the time of administration. It is concluded that the neuroendocrine elements of the hypothalamo-pituitary unit in mature female rats exhibit cyclic as well as diurnal alterations in the responsiveness to PGE2.

Induction of prolactin receptors in the liver is more closely related to the growth-promoting than to the lactogenic potency of peptides

1987 ◽  
Vol 114 (3) ◽  
pp. 350-356 ◽  
Author(s):  
G. Norstedt ◽  
B. Husman ◽  
A. Mode ◽  
P. Eneroth ◽  
U.J. Lewis ◽  
...  
Keyword(s):  
Time Course ◽  
Mature Female ◽  
Female Rats ◽  
Male Rats ◽  
Female Rat ◽  
Hypophysectomized Rats ◽  
Liver Membranes ◽  
Growth Promoting ◽  
Rat Livers

Abstract. The sex differentiated binding 125I-human prolactin (PRL) to rat liver membranes was studied and the present results extend our previous studies on induction of hepatic PRL receptors by growth hormone (GH). In prepubertal female rats, PRL receptor levels are low compared with those in mature female rat livers. Infusion of hGH during one week to 17-day-old female rats resulted in a receptor level typical of adult female rats. The time course of receptor disappearance in male rats treated with hGH was also studied. When the receptor-inducing hormone was removed, receptor levels in hGH-treated male rats returned to the normal level characteristic of male rats after approximately 96 h. The specificity of various GH-like and PRL-like hormones in PRL receptor induction was studied in hypophysectomized rats. The PRL-like hormones were identified by measuring their potency to displace 125I-hPRL from a receptor preparation obtained from female rat livers, and the GH-like hormones were identified by their potency to increase body weight in hypophysectomized rats. Using similar doses of hormones it was found that in vivo administration of growth-promoting peptides (rGH, hGH, bGH) induced PRL receptors, whereas lactogenic hormones (rPRL, hPL) had a very small or no effect on PRL receptor induction. This suggests that binding to a type of GH receptor is the first step in PRL receptor induction.

Fructose and glucose ingestion and muscle glycogen use during submaximal exercise

1983 ◽  
Vol 55 (6) ◽  
pp. 1767-1771 ◽  
Author(s):  
L. Levine ◽  
W. J. Evans ◽  
B. S. Cadarette ◽  
E. C. Fisher ◽  
B. A. Bullen
Keyword(s):  
Muscle Glycogen ◽  
Gastrocnemius Muscle ◽  
Respiratory Exchange Ratio ◽  
Venous Blood ◽  
Serum Glucose ◽  
Submaximal Exercise ◽  
Glycogen Depletion ◽  
O2 Uptake ◽  
Water Ingestion ◽  
Glucose Ingestion

Substrate utilization after fructose, glucose, or water ingestion was examined in four male and four female subjects during three treadmill runs at approximately 75% of maximal O2 uptake. Each test was preceded by three days of a carbohydrate-rich diet. The runs were 30 min long and were spaced at least 1 wk apart. Exercise began 45 min after ingestion of 300 ml of randomly assigned 75 g fructose (F), 75 g glucose (G), or control (C). Muscle glycogen depletion determined by pre- and postexercise biopsies (gastrocnemius muscle) was significantly (P less than 0.05) less during the F trial than during C or G. Venous blood samples revealed a significant increase in serum glucose (P less than 0.05) and insulin (P less than 0.01) within 45 min after the G drink, followed by a decrease (P less than 0.05) in serum glucose during the first 15 min of exercise, changes not observed in the C or F trials. Respiratory exchange ratio was higher (P less than 0.05) during the G than C or F trials for the first 5 min of exercise and lower (P less than 0.05) during the C trial compared with G or F for the last 15 min of exercise. These data suggest that fructose ingested before 30 min of submaximal exercise maintains stable blood glucose and insulin concentrations, which may lead to the observed sparing of muscle glycogen.

scholarly journals Effect of insulin on glucose transport and metabolism in isolated fat-cells of gonadal adipose tissue from mature age-matched male and female rats

1985 ◽  
Vol 225 (2) ◽  
pp. 343-348 ◽  
Author(s):  
M Guerre-Millo ◽  
A Leturque ◽  
M Lavau ◽  
J Girard
Keyword(s):  
Glucose Transport ◽  
Insulin Action ◽  
Insulin Binding ◽  
Mature Female ◽  
Female Rats ◽  
Male Rats ◽  
Total Lipids ◽  
Male And Female Rats ◽  
Glucose Incorporation ◽  
Higher Sensitivity

Insulin action on glucose transport and metabolism was studied in paraovarian adipocytes from 3-month-old female rats and compared with insulin action in epididymal adipocytes from closely age-matched males. At maximal insulin concentrations the stimulations of 2-deoxyglucose uptake (4-fold the basal value) and of [U-14C]glucose incorporation into CO2 and total lipids (3- and 2-fold the basal values respectively) were similar in adipocytes from rats of both sexes. At submaximal insulin concentrations (less than 0.2 nM) the ability of paraovarian adipocytes to transport and to metabolize glucose was higher than that of epididymal adipocytes; accordingly an increase in insulin binding was observed in paraovarian adipocytes as compared with epididymal adipocytes. These results show that paraovarian adipocytes from mature female rats were highly responsive to insulin, and exhibited a higher sensitivity to the hormone than did epididymal adipocytes from male rats of the same age.

scholarly journals 17β-Estradiol restores excitability of a sexually dimorphic subset of myelinated vagal afferents in ovariectomized rats

2009 ◽  
Vol 297 (3) ◽  
pp. C654-C664 ◽  
Author(s):  
Guo-Fen Qiao ◽  
Bai-Yan Li ◽  
Yan-Jie Lu ◽  
Yi-Li Fu ◽  
John H. Schild
Keyword(s):  
Estrogen Receptor ◽  
Neuronal Excitability ◽  
Vagal Afferents ◽  
Female Rats ◽  
Male Rats ◽  
Ovariectomized Rats ◽  
Cellular Mechanisms ◽  
Patch Clamp Technique ◽  
17Β Estradiol ◽  
Vagal Afferent

We recently identified a myelinated vagal afferent subpopulation (Ah type) far more prevalent in female than male rats and showed that this difference extends to functionally specific visceral sensory afferents, baroreceptors of the aortic arch. Excitability of myelinated Ah-type afferents is markedly reduced after ovariectomy (OVX). Here we tested the hypothesis that 17β-estradiol can selectively restore excitability of these sex-specific vagal afferents. Acutely isolated vagal afferent neurons (VGN) from intact and OVX adult female rats were used with patch-clamp technique and current-clamp protocols to assess the effect of acute application of 17β-estradiol on neuronal excitability. At over physiologically relevant 17β-estradiol concentrations for rat (1–10 nM) excitability of myelinated Ah-type vagal afferents is restored to discharge frequencies comparable to those in intact females, albeit with some interesting differences related to burst and sustained patterns of neuronal discharge. Restoration of excitability occurs within 3 min of hormone application and is stereo specific, because 1,000 nM 17α-estradiol fails to alter excitability. Furthermore, activation of G protein-coupled estrogen receptor GPR30 with highly selective agonist G-1 similarly restores excitability of Ah-type afferents. The effectiveness of 17β-estradiol and G-1 is completely eliminated by application of high-affinity estrogen receptor ligand ICI-182,780. 17β-Estradiol conjugated with BSA is ∼70% as effective as 17β-estradiol alone in restoring Ah-type VGN excitability. These data support our conclusions that the cellular mechanisms leading to rapid restoration of neuronal excitability of myelinated Ah-type VGN after OVX occur, at least in part, via membrane-bound estrogen receptors. We contend that recovery of high-frequency discharge at physiologically relevant 17β-estradiol concentrations implies that this unique subtype of low-threshold myelinated vagal afferent may account for some of the sex-related differences in visceral organ system function. Sex differences in cardiovascular and gastrointestinal function and the potential role of GPR30 in modulation of sex-specific myelinated Ah-type vagal afferents are discussed.

Liver glycogenolysis during exercise in adrenodemedullated male and female rats

1986 ◽  
Vol 251 (6) ◽  
pp. R1151-R1155
Author(s):  
W. W. Winder ◽  
S. F. Loy ◽  
D. S. Burke ◽  
S. J. Hawkes
Keyword(s):  
Adrenergic Receptor ◽  
Mature Female ◽  
Female Rats ◽  
Male Rats ◽  
Plasma Epinephrine ◽  
Male And Female ◽  
Male And Female Rats ◽  
Liver Glycogenolysis ◽  
Stimulation Of

Previous studies have shown that adrenodemedullation has no effect on the rate of liver glycogenolysis during exercise in male rats. Mature female rats have been reported to have a higher hepatic beta-adrenergic receptor activity than do male rats of the same age. The present study was undertaken to determine the role of plasma epinephrine in stimulating liver glycogenolysis during exercise in female rats. Both male and female rats were adrenodemedullated or sham operated. Three weeks later rats were run for 60 min at 21 m/min up a 15% grade. The rate of liver glycogenolysis during exercise was not affected by adrenodemedullation in either female rats or male rats. Hepatic adenosine 3',5'-cyclic monophosphate increased to approximately the same extent in sham operated as in adrenodemedullated female rats during exercise. Adrenodemedullation caused a significant reduction in the amount of glycogen utilized by the soleus muscle and in the degree of hyperglycemia during exercise. We conclude that epinephrine is unessential for stimulation of liver glycogenolysis during exercise in either male or female rats.

THE EFFECTS OF SEX STEROIDS ON THE PROLACTIN CONTENT OF HYPOPHYSES AND SERUM IN RATS

1963 ◽  
Vol 43 (1) ◽  
pp. 137-146 ◽  
Author(s):  
O. L. Wolthuis
Keyword(s):  
Sex Steroids ◽  
Testosterone Propionate ◽  
Mature Female ◽  
Mature Male ◽  
Female Rats ◽  
Male Rats ◽  
List Type ◽  
Oestradiol Benzoate ◽  
Prolactin Content ◽  
Pituitary Prolactin

ABSTRACT Prolactin determinations have been carried out on the hypophyses and serum of rats. It was found that: Hypophyses of intact mature female rats contain almost twice as much prolactin as those of mature female rats spayed two months previously. The pituitary prolactin content in these spayed female rats is virtually identical with that of intact or castrated mature male rats. Treatment of intact mature female rats with oestradiol benzoate (50 μg daily for one week) considerably increases the prolactin content in the hypophyses and serum. Treatment of spayed mature female rats with sex steroids for two weeks shows that: oestradiol benzoate (50 μg daily) increases the prolactin content in the hypophyses and serum; testosterone propionate (2 mg daily) also increases the prolactin content in the hypophyses and serum, although the increases found were smaller than those obtained with the above-mentioned dose of oestradiol; progesterone (5 mg daily) did not significantly alter the pituitary prolactin content, whereas a highly suggestive increase was found in the serum content. From the results it was concluded that: Physiological amounts of androgens do not affect the prolactin function of the hypophysis, whereas physiological amounts of oestrogens do affect it. All three sex steroids investigated increase prolactin production in and secretion from the hypophysis. A negative feedback seems to be absent.

PITUITARY CONTROL OF BLOOD COAGULATION IN THE RAT

1981 ◽  
Vol 91 (3) ◽  
pp. 367-373 ◽  
Author(s):  
ETSUKO KITA ◽  
CORAL A. LAMARTINIERE
Keyword(s):  
Blood Coagulation ◽  
Sexual Differentiation ◽  
Coagulation Factors ◽  
Mature Female ◽  
Activated Partial Thromboplastin Time ◽  
Female Rats ◽  
Male Rats ◽  
Clotting Time ◽  
Male And Female Rats ◽  
Pituitary Glands

Assay of prothrombin time, activated partial thromboplastin time and activity in the thrombotest in the rat showed that at 14 days of age, male and female rats had similar activities but female rats of 21–84 days of age had higher blood coagulation activities than male rats. Coagulation in mature female animals was not affected by the stage of the oestrous cycle. Hypophysectomy of prepubertal (21 days old) or adult (56 days old) male or female animals resulted in lower activity (prolongation of clotting time). A pituitary gland implanted ectopically under the kidney capsule of hypophysectomized animals resulted in shorter clotting times than in hypophysectomized animals not so treated. Pituitary glands from female donors were more effective in recipients of both sexes than those from males. These results demonstrate a sexual differentiation in activity of coagulation factors in the rat and suggest the involvement of the hypothalamic–hypophysial–gonadal axis in the regulation of blood coagulation.

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