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Biomedical subjects

V D Castracane

Publications and source records attributed to V D Castracane.

At least 37 records · Page 2Linked to original sources
PubMed1999

Effects of aerobic exercise on serum leptin levels in obese women.

It has been demonstrated that leptin concentrations in obese patients may be altered by weight loss. We examined the effects of a 9-week aerobic exercise program on serum leptin concentrations in overweight women (20-50% above ideal body mass) under conditions of weight stability. Sixteen overweight women, mean (SE) age 42.75 (1.64) years, comprised the exercise group which adhered to a supervised aerobic exercise program. A graded exercise treadmill test was conducted before and after the exercise program to determine maximal oxygen uptake (VO2max) using open-circuit spirometry. The women demonstrated improved aerobic fitness (VO2max increased 12.29%), however, body fat and the body mass index did not change significantly [42.27 (1.35)-41.87 (1.33)%]. Fourteen women, age 40.57 (2.80) years, did not exercise over the same time period and served as a control group. Serum leptin levels were not significantly altered for either the exercise [28.00 (2.13)-31.04 (2.71) ng x ml(-1)] or the control group [33.24 (3.78)-34.69 (3.14) ng x mg(-1)]. The data indicate that 9 weeks of aerobic exercise improves aerobic fitness, but does not affect leptin concentrations in overweight women.

Adult↗
PubMed1999

Serum leptin concentrations in response to acute exercise in postmenopausal women with and without hormone replacement therapy.

The purpose of the study was to examine the effects of acute exercise and hormone replacement therapy on serum leptin concentrations in postmenopausal women. Subjects were 15 healthy, postmenopausal women, 8 on hormone replacement therapy (HRT) and 7 not on hormone replacement therapy (NHRT). Group comparisons indicated no significant differences between HRT and NHRT groups with respect to age, height, weight, BMI, sum of skinfolds, or VO2max, and verified significant differences in estradiol and FSH concentrations. After an overnight fast, each subject completed 30 min of treadmill exercise at approximately 80% VO2max. Over 2 hr and 10 min, baseline, exercise, and recovery blood samples were collected from an intravenous catheter. A control session conducted a month later consisted of the same blood sampling protocol without exercise. Leptin concentrations declined significantly over the course of both the exercise and control sessions, gradually decreasing from baseline levels to -1.54 +/- 0.49 ng. ml-1 postexercise, and continuing to decline to a low of -2.89 +/- 0.59 ng. ml-1 at the end of the session. There was no significant difference between groups with respect to this decline. This is the first study to document that diurnal changes in leptin concentrations in postmenopausal women are not altered by acute treadmill exercise or HRT status. The study underscores the need to account for a diurnal reduction in leptin over the course of an exercise trial.

Blood Proteins↗
PubMed1999

Circannual changes in free thyroxine, prolactin, testes, and relative food intake in woodchucks, Marmota monax.

Woodchucks (n = 12-14/group) with circannual cycles entrained to northern versus southern hemisphere photoperiods were assessed monthly for 16 mo. Changes in serum total triiodothyronine (TT(3)), free thyroxine (T(4)), total thyroxine (TT(4)), and prolactin were determined in a subset of five animals per group. Metabolic hormone results were examined in relation to changes in body weight, food intake, and serum testosterone (n = 12-14/group). Seasonal changes in each parameter were similar in both groups as were nadir and peak TT(3) (162 +/- 6 and 392 +/- 12 ng/ml, respectively), free T(4) (19 +/- 2 and 86 +/- 7 ng/ml, repectively), TT(4) (3.2 +/- 0.2 and 8.0 +/- 0.5 ng/ml, respectively), and prolactin (0.6 +/- 0.1 and 14 +/- 2 ng/ml, respectively). In late winter and early spring, simultaneous increases in both free T(4) and prolactin were associated with 1) a large increase in food intake, 2) a decline in body weight to nadir values, 3) a corresponding negative energy balance, 4) a peak and decline in serum testosterone, and 5) a modest increase in TT(4) and large decline in serum TT(3). Low levels of free T(4) and prolactin were observed in summer when energy balance was very positive. The results demonstrate that, in woodchucks, serum T(4) and prolactin undergo seasonal changes during annual cycles entrained by photoperiod. The results suggest that changes in free T(4), acting as a calorigenic hormone, and changes in both T(4) and prolactin, potentially acting as lipolytic, antilipogenic, and/or orectic hormones, are likely involved in the mechanisms underlying the corresponding seasonal changes in food intake, fat metabolism, and energy balance in this species. Their potential roles in gonadal regression and recrudescence are less clear.

Animals↗
PubMed1999

Serum leptin concentrations and expression of leptin transcripts in placental trophoblast with advancing baboon pregnancy.

Leptin is a polypeptide hormone originally thought to be produced exclusively by adipocytes. Recently, however, both leptin messenger ribonucleic acid (mRNA) and leptin protein were identified in human placental trophoblast cells, suggesting a potential role in primate pregnancy. In the present study, venous blood samples were collected at 5-day intervals during gestation from baboons (Papio sp), an established model for the study of human pregnancy, as well as from nonpregnant baboons, and leptin concentrations were determined by RIA. Additionally, placental villous tissue was collected upon cesarean delivery at early (days 60-62; n = 5), mid (days 98-102; n = 5), and late (days 159-167; n = 5) gestation (term = approximately 184 days), and leptin mRNA was quantitated by competitive RT-PCR. Finally, in situ hybridization was employed to localize transcripts to specific placental cell types. Results determined that maternal leptin levels (mean +/- SEM), which were dramatically greater (P<0.01) than those in nonpregnant cycling baboons (1.4+/-0.1 ng/mL), increased (P<0.005) with gestational age from 63.6+/-10.4 ng/mL on day 60 of gestation to 157.8+/-16.1 near term. Levels declined to those found in cycling baboons by 15 days postdelivery. In contrast to maternal leptin concentrations, placental leptin mRNA decreased (P<0.02) with advancing pregnancy, as transcript abundance declined approximately 8-fold from early to late gestation. Maternal peripheral leptin concentrations were positively correlated (r = 0.66; P<0.001) whereas placental leptin mRNA levels were negatively correlated (r = -0.64; P<0.01) with gestational age. Expression of leptin mRNA transcripts, as evidenced by RT-PCR in villous tissue, was localized principally within syncytiotrophoblast by in situ hybridization. In summary, changes in maternal peripheral leptin concentrations and placental leptin mRNA abundance that occur commensurate with advancing gestational age may imply evolving roles for the polypeptide with advancing primate pregnancy. In this capacity, localization of leptin transcripts within the baboon syncytiotrophoblast suggests the potential for autocrine or paracrine interactions within this endocrinologically active tissue. Finally, both the similarities in leptin ontogeny in baboon and human pregnancy and the singular enhancement of maternal leptin levels inherent throughout baboon gestation emphasize the potential of this nonhuman primate model for the study of leptin action in the maternal-fetoplacental unit.

Animals↗
PubMed1998

Endocrine responses during exercise-heat stress: effects of prior isotonic and hypotonic intravenous rehydration.

Exercise following exercise-induced dehydration (EID) has been shown to elevate concentrations of plasma norepinephrine (NE) and hypothalamic-pituitary-adrenal axis hormones. However, it is not known how intravenous (i.v.) rehydration (Rh) with isotonic (ISO) or hypotonic (HYPO) saline affects these hormone concentrations. It was hypothesized that HYPO, versus ISO, would lead to lower plasma NE and cortisol concentrations ([CORT]) during subsequent exercise following EID due to a decrease in plasma sodium concentration [Na+]. Eight non-heat acclimated men completed three experimental treatments (counterbalanced design) immediately following EID (33 degrees C) to -4% body mass loss. The Rh treatments were i.v. 0.9% NaCl (ISO, 25 ml x kg[-1]), i.v. 0.45% NaCl (HYPO, 25 ml x kg[-1]), and no fluid (NF). After Rh and rest (2 h total), the subjects walked at 53-54 percent of maximal O2 uptake for 45 min at 36 degrees C. After Rh, the following observations were made before/during exercise: percentage change in plasma volume (PV) was lower in NF compared to ISO and HYPO but similar between ISO and HYPO; delta[Na+] was similar between ISO and NF and higher in ISO compared to HYPO; delta plasma NE was higher in NF compared to ISO and HYPO, but similar between ISO and HYPO; delta plasma [CORT] was higher in NF compared to ISO and HYPO and higher in ISO compared to HYPO; rectal temperature was higher in NF compared to ISO and HYPO. These data would suggest that sympathetic nervous activity and [CORT] during exercise, subsequent to EID and Rh, was affected by lower PV (probably through cardiopulmonary baroreflexes) as well as core temperature. Furthermore, [CORT] was affected by delta[Na+] after Rh through an unknown mechanism.

Adult↗
PubMed1998

Serum leptin concentration in women: effect of age, obesity, and estrogen administration.

OBJECTIVE: To compare serum leptin levels in normally cycling reproductive females (20-35 years old) with those in age-matched males, in women who were receiving oral contraceptives, and in older (postmenopausal) women (50-65 years old) who were or who were not receiving hormone replacement therapy. DESIGN: Case-control study. SETTING: Obstetrics and Gynecology Clinic, Texas Tech University Health Sciences Center-Amarillo, or the Exercise Physiology Laboratory at Southeastern Louisiana University. PATIENT(S): Normally cycling women between the ages of 20-35 years and age-matched controls who were receiving oral contraceptives. Postmenopausal women between the ages of 50-65 years who were or who were not receiving hormone replacement therapy. MAIN OUTCOME MEASURE(S): Serum leptin concentration. RESULT(S): In all groups, serum leptin concentrations were correlated significantly with body mass index. Leptin levels were significantly higher in young women than young men (P <.001), but no other statistically significant differences were found for the other three comparisons. CONCLUSION(S): Serum leptin concentrations expressed as a measure of adiposity (body mass index) are greater in young normally cycling females (20-35 years old) than in age-matched males. There is no difference in levels of serum leptin between young and postmenopausal (50-65 years old) women. Estrogen administration, either in young women who are receiving estrogen-progestin oral contraceptives or in postmenopausal women who are receiving hormone replacement therapy, does not effect serum leptin concentrations.

Adult↗
PubMed1998

Maternal serum androgens in human pregnancy: early increases within the cycle of conception.

Previous studies have demonstrated elevations in testosterone and androstenedione initiated within the cycle of conception in pregnant non-human primates, and minimal data in the human support the same picture. In the present study we have investigated a group of patients scheduled for artificial insemination with regular menstrual cycles. For this study all patients provided blood samples at 5 days after the luteinizing hormone (LH) surges and daily through the luteal phase and into early pregnancy (n = 12). Patients who did not become pregnant served as normal controls (n = 9). We have measured 17-hydroxyprogesterone (17-OHP) as a marker of luteal activity not obscured by progesterone within the cycle of conception and testosterone and androstenedione as the major androgens. There were no significant changes in testosterone and androstenedione in the non-pregnant controls, but both testosterone and androstenedione were significantly elevated in the pregnant luteal phase, with the first increases occurring at 15 and 14 days respectively after the LH surge. Three of 12 pregnant patients did not demonstrate a dramatic increase in either testosterone or androstenedione and when examined more carefully a corresponding lack of increase in 17-OHP in those same subjects indicated less than optimal luteal activity, suggesting that these androgens were products of the corpus luteum. In three subjects in which consecutive non-pregnant and pregnant cycles were followed there was a dramatic increase from the non-pregnant luteal phase to the pregnant luteal phase indicating that the more important observation may be the concentrations of androgens in the conceptive luteal phase compared to some baseline, either previous luteal phase or even follicular phase. We have also studied changes in dehydroepiandrosterone sulphate and found that there was no significant contribution to this increase in androgens in early conception. These studies demonstrate a significant increase in both testosterone and androstenedione presumably of ovarian, specifically luteal, origin and that adrenal androgen production is not a factor in these changes.

17-alpha-Hydroxyprogesterone↗
PubMed1998

The effect of dexamethasone administration at different stages of gestation on maternal plasma steroid concentrations in the baboon (Papio cynocephalus).

Dexamethasone administration at different stages of gestation in the baboon was studied for its effect on maternal steroid hormone concentrations. Dexamethasone (2 mg i.m. at 12 h intervals for three doses) was administered at early (days 37-39), mid (days 76-85) or late (days 112-123) gestation and morning blood samples were collected before, during and after dexamethasone suppression for 6 consecutive days. Dexamethasone treatment, at all stages of pregnancy, resulted in a significant decline in maternal serum cortisol concentrations, which rapidly return to normal concentrations after treatment. Progesterone concentrations were not affected by dexamethasone at any stage of gestation. Serum concentrations of oestradiol, testosterone and androstenedione were unchanged following dexamethasone administration in early pregnancy. A trend toward lower serum oestradiol was observed following dexamethasone administration in both mid and late gestation, but this was not significant. Both testosterone and androstenedione were significantly decreased following dexamethasone in both mid and late pregnancy and recovered to pretreatment concentrations within a few days after cessation of treatment. These results confirm other studies which demonstrate that adrenal precursors (maternal or fetal) are a major contributor to maternal serum concentrations of oestradiol. They also demonstrate that these adrenal precursors increase serum concentrations of testosterone and androstenedione in the pregnant baboon. Since these changes are only evident after that time (>40 days) when the fetal adrenal is steroidogenically competent, a role for fetal adrenal involvement in maternal serum androgen concentrations is suggested.

Adrenal Glands↗
PubMed1998

Effects of hormone replacement on growth hormone and prolactin exercise responses in postmenopausal women.

Exercise elevates growth hormone (GH) and prolactin (PRL) blood concentrations in premenopausal women. Postmenopausal women taking hormone replacement therapy (HRT) maintain higher estrogen levels that could affect GH and PRL. The purpose of the study was to determine the effects of HRT on GH and PRL responses to treadmill exercise. Seventeen healthy women who were postmenopausal (naturally or surgically) [8 on HRT; 9 not on HRT (NHRT)], completed 30 min of treadmill exercise at 79.16 +/- 1.2% maximal O2 consumption (HRT group) and 80.19 +/- 0.91% maximal O2 consumption (NHRT) group). Blood samples were collected from an intravenous catheter during an exercise session and during a control session without exercise. GH and PRL concentrations were significantly higher in the exercise trial than in the nonexercise trial, whereas resting concentrations were similar for both trials. GH and PRL peaked at 10.8 +/- 1.60 and 12.67 +/- 2.58 ng/ml, respectively, for HRT subjects and at 4.90 +/- 1.18 and 9.04 +/- 2.17 ng/ml, respectively, for NHRT subjects. GH concentrations in the exercise trial were significantly higher for HRT than for NHRT subjects. This is the first study to demonstrate that HRT enhances treadmill-exercise-induced GH release and that similar PRL responses to treadmill exercise occur in postmenopausal women regardless of HRT status.

Estrogen Replacement Therapy↗
PubMed1998

Rapid, convenient radioimmunoassay of estrone sulfate.

We developed a specific, simple, and rapid RIA for the direct quantification of estrone sulfate (E1S) and established its performance characteristics. The assay has a dynamic range of 0.05-90 micrograms/L with a detection limit of 0.009 microgram/L. Intraassay CVs were 9.2%, 4.5%, and 4.6% at 0.35, 9.0, and 60 micrograms/L, respectively. Interassay CVs were 8.8%, 5.1%, and 5.5% at 0.076, 0.5, and 12 micrograms/L, respectively. Linearity of dilution studies showed values of 80-105% of expected, and recovery of E1S added to serum samples ranged from 82% to 102%. Cross-reactivities with structurally related estrogens were < 5%. When compared with a conventional assay (involving hydrolysis of E1S and indirect measurement of estrone), the present RIA showed excellent correlation (r = 0.99, slope = 1.54, Sy/x = 2.14, n = 71). Mean E1S concentrations measured with this RIA for normal men (n = 20) and women in follicular (n = 20) and luteal (n = 25) phases of their menstrual cycle were 0.96, 0.96, and 1.74 microgram/L, respectively. Mean E1S concentrations for oral contraceptive users (n = 20) and postmenopausal women without hormone replacement therapy (n = 21) or on hormone replacement therapy (n = 22) were 0.74, 0.13, and 2.56 micrograms/L, respectively. Serum concentrations of E1S in pregnant women in their first (n = 14), second (n = 17), and third (n = 15) trimesters were 20, 66, and 105 micrograms/L, respectively. Availability of this simple RIA should provide a useful tool for the assessment of estrogen status in women.

Cross Reactions↗
PubMed1997

Comparison of three methods for 17 alpha-hydroxyprogesterone.

We compared the performance of three 17 alpha-hydroxyprogesterone kits: the double antibody method, the coated tube method (ACTIVE), both from Diagnostic Systems Laboratories, Inc. (DSL) and the coated tube method (COAT-A-COUNT) from Diagnostic Products Corporation (DPC). The assay performance of the two DSL kits was very similar in terms of sensitivity, intra- and inter-assay precision, linearity of dilution, recovery, and specificity. We also analyzed 190 samples for 17 alpha-hydroxyprogesterone values using the above three kits. Twenty-three subjects were from prepubertal population (ages 1 month-13 years), thirty subjects were normal adult males (ages 20-53 years) and the remaining subjects were females in different phase of menstrual cycle (n = 40), on oral contraceptives (n = 20), post-menopausal (n = 17), or pregnant women in their first, second, or third trimester (n = 60). In addition to these 60 pregnancy samples, we analyzed serial samples from 3 pregnancies. 17 alpha-OHP levels paralleled the progesterone levels in all three kits. Although there was reasonable correlation between the DPC and the two DSL kits, the 17 alpha-OHP values were found to be significantly higher with DPC kit during the 2nd and 3rd trimester of pregnancy indicating probable interference in the DPC assay by some structurally related steroids present during pregnancy. The DSL assays may be particularly well suited for measuring 17 alpha-OHP levels during pregnancy.

17-alpha-Hydroxyprogesterone↗
PubMed1997

Effects of estrogen replacement therapy on dehydroepiandrosterone, dehydroepiandrosterone sulfate, and cortisol responses to exercise in postmenopausal women.

OBJECTIVE: To determine the effects of hormone replacement therapy (HRT) on dehydroepiandrosterone (DHEA), DHEA sulfate (DHEAS), and cortisol (F) responses to treadmill exercise. DESIGN: Controlled clinical study. SETTING: Female volunteers in an academic research environment. PATIENT(S): Sixteen healthy, postmenopausal women (7 were receiving HRT, 9 were not). INTERVENTION(S): Blood samples were taken from an intravenous catheter before, during, and after 30 minutes of treadmill exercise following an overnight fast. A second session was conducted one month later for the same subjects using the same blood sampling protocol without exercise. MAIN OUTCOME MEASURE(S): Serum DHEA, DHEAS, and F concentrations. RESULT(S): The HRT and untreated DHEA area under the curve (AUC) for the exercise trials was significantly greater than that for the control trials. The untreated, but not the HRT, DHEAS AUC for the exercise trials was significantly greater than that for the control trials. The HRT and untreated F AUC for the exercise trials was significantly greater than that for the control trials. The AUC for the HRT exercise trials was significantly higher than the untreated exercise trials for DHEA and F, but not DHEAS. CONCLUSION(S): Data suggest that treadmill exercise elevates DHEA, DHEAS, and F levels in postmenopausal women and that HRT enhances the DHEA and F responses.

Adrenocorticotropic Hormone↗
PubMed1997

Prolonged inhibition of normal ovarian cycles in the rat and cynomolgus monkeys following a single s.c. injection of danazol.

In castrated male rats, a single s.c. injection of danazol has been shown to result in an inordinately prolonged inhibition of serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) concentrations. In the present study, we have examined whether the same and similar routes of administration suppresses ovarian function in normally cycling rats and cynomolgus monkeys. Normally cycling female rats received danazol as a single administration either orally, i.m. or s.c. and a separate group also received danazol in silastic capsules. The duration of the dioestrous interval until the next oestrous smear was followed daily and cycle lengths were compared with vehicle-treated groups. Six normally cycling cynomolgus monkeys were followed by daily observation and blood sampling at 2-3 day intervals. After one normal cycle, danazol (200 mg/kg) was administered as a single s.c. injection. Monkeys were followed until the next menses and one cycle thereafter and blood samples were assayed for oestradiol, progesterone and bioactive LH. Oestrous cycle length in vehicle-treated control rats was 4.7 days. A single administration of danazol s.c. at the higher dose prolonged the dioestrous interval to 31.3 days (P <0.001) and a similar prolongation was observed with this high dose when administered i.m. (27.7 days; P <0.001). In normally cycling monkeys, the menstrual cycle length was 30.2 days, but following a single danazol administration, the mean duration to the next menses was prolonged to 117.5 days (P <0.001). In five out of six monkeys, there was a decrease in LH and an absence of normal oestradiol and progesterone patterns. After this prolonged hiatus, a subsequent menstrual cycle was normal in length and endocrine pattern. A single s.c. administration of danazol resulted in a prolonged suppression of ovarian cyclicity in both normally cycling rats and cynomolgus monkeys.

Animals↗
PubMed1997

Intravenous vs. oral rehydration: effects on subsequent exercise-heat stress.

This study compared the influence of intravenous vs. oral rehydration after exercise-induced dehydration during a subsequent 90-min exercise bout. It was hypothesized that cardiovascular, thermoregulatory, and hormonal variables would be the same between intravenous and oral rehydration because of similar restoration of plasma volume (PV) and osmolality (Osmo). Eight non-heat-acclimated men received three experimental treatments (counterbalanced design) immediately after exercise-induced dehydration (33 degrees C) to -4% body weight loss. Treatments were intravenous 0.45% NaCl (iv; 25 ml/kg), no fluid (NF), and oral saline (Oral; 25 ml/kg). After rehydration and rest (2 h total), subjects walked at 50% maximal O2 consumption for up to 90 min at 36 degrees C. The following observations were made: 1) heart rate was higher (P < 0.05) in Oral vs. iv at minutes 45, 60, and 75 of exercise; 2) rectal temperature, sweat rate, percent change in PV, and change in plasma Osmo were similar between iv and Oral; 3) change in plasma norepinephrine decreased less (P < 0.05) in Oral compared with iv at minute 45; 4) changes in plasma adrenocorticotropic hormone and cortisol were similar between iv and Oral after exercise was initiated; and 5) exercise time was similar between iv (77.4 +/- 5.4 min) and Oral (84.2 +/- 2.3 min). These data suggest that after exercise-induced dehydration, iv and Oral were equally effective as rehydration treatments. Thermoregulation, change in adrenocorticotropic hormone, and change in cortisol were not different between iv and Oral after exercise began; this is likely due to similar percent change in PV and change in Osmo.

Adult↗
PubMed1996

Evidence for diminished midcycle ovarian androgen production in older reproductive aged women.

OBJECTIVE: To test the hypothesis that reproductive aging is associated with menstrual cycle-related decreases in androgen secretion. DESIGN: Comparison of cross-sectional data. SETTING: University teaching hospital. PATIENTS: Two groups of seven women were studied; midreproductive aged (19 to 37 years old) and older reproductive aged (43 to 47 years old). All patients were cycling regularly and had normal PRL and TSH. INTERVENTIONS: Patients underwent blood sampling during selected days of the menstrual cycle. MAIN OUTCOME MEASURE: After establishing the date of the midcycle surge, specimens were measured on selected days for androstenedione (A), total T, free T, and sex hormone-binding globulin (SHBG) using commercially available reagents. RESULTS: Sex hormone-binding concentrations did not vary across the menstrual cycle and did not differ between older and younger women. Total T did not differ significantly at any cycle stage between older and younger women. However, the midcycle rise in free T and A seen in younger women was consistently and significantly absent in the older women. CONCLUSIONS: In the absence of significant changes in SHBG associated with older reproductive age, the finding of diminished concentrations of both free T and A suggests that these hormones are produced in lesser quantity at midcycle in older women. Because the changes we noted depended on menstrual cycle stage, our findings suggest that an ovarian and not adrenal process is involved.

Adult↗
PubMed1996

Gonadotropin-releasing hormone agonist and human menopausal gonadotropin (hMG) short protocol, but not hMG alone, rescues the corpus luteum from the preceding cycle.

OBJECTIVE: To determine whether ovulation induction regimens, particularly the short protocol, has an effect on the corpus luteum (CL) from the previous cycle. DESIGN: Infertility patients were followed in an academic research environment. Patients were treated with either the short protocol (GnRH agonist [GnRH-a] and hMG) or hMG alone in a controlled ovarian hyperstimulation cycle. SETTING: Infertility center in academic setting. PATIENTS: Patients requiring ovulation induction. INTERVENTIONS: The blood samples were drawn on day 2 or 3 as a baseline before initiation of any treatments, generally on day 5 and usually every other day thereafter until ovulation. Serum P, E2, and relaxin were determined. MAIN OUTCOME MEASURES: Serum P, E2 and relaxin. RESULTS: Patients receiving hMG alone showed no change in serum P levels in the first few days of treatment whereas most short-protocol patients (18/30; 60%) showed an increase of P within 3 days of the initiation of treatment. The increase in P almost always was associated with an increase in relaxin as a marker of the luteal production of this P. CONCLUSION: The short protocol with its flare of gonadotropins is able to stimulate the CL from the previous cycle, resulting in an early increase in P that comes from the CL as indicated by its association with an increased relaxin in the same subjects.

Corpus Luteum↗
PubMed1996

Effects of low-volume resistive exercise on beta-endorphin and cortisol concentrations.

It has been recently suggested that high and sustained lactate levels may elicit increases in peripheral B-EN concentrations (16). We have observed elevated and sustained lactate concentrations in response to a low-volume resistive exercise protocol (14) that were similar to those from other exercise protocols that produced elevated beta-endorphin (B-EN) concentrations. Thus, the purpose of the study was to determine the effects of a low-volume (21,700 J) resistive exercise repetition maximum (RM) protocol using weight machines on peripheral lactate, B-EN and cortisol concentrations. Subjects completed 3 sets of bench press, lat-pull, leg extension, and leg curl exercise at a 10-RM load. Blood samples were collected and rating of perceived exertion (RPE, 15-point Borg scale) was assessed before exercise (-40 and -10 min), after each exercise, and after the exercise session (+ 35 min); blood samples were collected at 7 additional post-exercise times. RPE increased significantly throughout the exercise. Lactate concentrations rose significantly to peak at 8.54 mM at LE. B-EN and cortisol concentrations (-10) of 4.63 +/- 0.54 pmol.l-1 and 12.09 +/- 1.44 micrograms.dl-1, respectively, were not significantly elevated over time. The data suggest that a low-volume resistive exercise protocol using weight machines elevates lactate concentrations without altering B-EN and cortisol concentrations.

Adult↗