Disordered hypothalamus-pituitary-ovary axis in heterotopic extraovarian sex cord-stromal proliferation: a case report of fallopian tube serous adenofibroma.

BACKGROUND: Fallopian tube serous adenofibromas are uncommon tumors of the female genital tract, only dozens of cases have ever been reported. Earlier study indicated that they might be derived from embryonic remnants of the Müllerian duct. Clinical presentation of these tumors is usually asymptomatic. Small cysts of 0.5-3 cm in diameter are mostly incidentally found at the fimbriae end, with coarse papillary excrescences lined by epithelial cells and connective tissue stroma without nuclear pleomorphism or mitosis. CASE PRESENTATION: A 23-year-old woman with normal secondary sexual characters and 46, XX karyotype, presented to the gynecology clinic complaining of irregular menstrual cycles. Laboratory studies reported unique discrepancy of hormone levels; anti-Müllerian hormone (AMH): 6.05 ng/mL (The normal range of AMH is 1.70-5.63 ng/mL in women aged under 35 years old), follicle stimulating hormone (FSH): 31.9 mIU/mL (reference range: 3.85-8.78, follicular phase; 4.54-22.51, ovulatory phase; 1.79-5.12, luteal phase; 16.74-113.59, menopause), and luteinizing hormone (LH): 52.0 mIU/mL (reference range: 2.12-10.89, follicular phase; 19.18-103.03, ovulatory phase; 1.20-12.86, luteal phase; 10.87-58.64, menopause), mimicking gonadotropin-resistant ovary syndrome. The ultrasound reported a right adnexal cyst of 10.4 × 7.87 × 6.7 cm. Laparoscopic evaluation was performed; pathology revealed serous adenofibroma of the fallopian tube with ovarian stroma contents. Heterotopic extraovarian sex cord-stromal proliferations was most probable. The patient's hormone levels returned to the reproductive status two weeks after surgery; FSH: 7.9 mIU/mL, LH: 3.59 mIU/mL,and AMH: 4.32 ng/mL. The patient's menstrual cycles have resumed to normal for over two years after removal of the fallopian tube cyst. CONCLUSIONS: This case of fallopian tube serous adenofibromas presented a discrepancy of serum AMH and FSH mimicking gonadotropin-resistant ovary syndrome. The clinical picture derived from heterotopic extraovarian sex cord-stromal proliferation indicated a disordered hypothalamus-pituitary-ovary axis.

Intraovarian Injection of Recombinant Human Follicle-Stimulating Hormone for Luteal-Phase Ovarian Stimulation during Oocyte Retrieval Is Effective in Women with Impending Ovarian Failure and Diminished Ovarian Reserve.

It is a challenge to obtain sufficient eggs during in vitro fertilization (IVF) in women with impending ovarian failure (IOF)/diminished ovarian reserve (DOR). Although studies have suggested that more than one wave of follicle growth exists, the efficacy of controlled ovulation stimulation (COS) in both follicular and luteal phases of the same ovarian cycle (DuoStim) is not established in women with IOF/DOR. We investigated the efficacy of DuoStim using the intraovarian injection of recombinant human follicle-stimulating hormone (rhFSH) during oocyte retrieval in women with DOR. For luteal-phase stimulation, intraovarian (Group A, N = 28) or superficial subcutaneous (Group B, N = 18) injection of 300 IU rhFSH immediately after oocyte retrieval was administered as the first dose, and intermittent superficial subcutaneous addition of gonadotropins was employed accordingly for further COS in both groups. In Group A, significantly lower Gn doses, a shorter duration of COS, a greater number of antral follicle counts, and an increased number of retrieved mature and total oocytes were noted. Compared with the clinical outcomes of luteal-phase COS, the average daily doses of rhFSH used in Group A were significantly lower. In summary, the novel approach using intraovarian rhFSH injection provides an efficient treatment regimen in women with IOF/DOR.

Ovarian Follicular Growth through Intermittent Vaginal Gonadotropin Administration in Diminished Ovarian Reserve Women.

It is a challenge to obtain enough oocytes during in vitro fertilization (IVF) in women who have a poor ovarian response (POR) in achieving conception. We have adopted the characteristics of the first uterine pass effect, which we pioneered in employing the vaginal administration of gonadotropins in women receiving IVF treatments. In our previous study employing vaginal administration, faster absorption and slower elimination of gonadotropins were demonstrated, and, female subjects presented proper ovarian follicle growth and pregnancy rates. In this study, during 2016-2020, 300 to 675 IU of gonadotropins were administered vaginally every three days in 266 POR women for their controlled ovarian hyperstimulation (COH). The injections were performed with needles angled at 15-30° towards the middle-upper portions of the bilateral vaginal wall, with an injection depth of 1-2 mm. For the COH results, these women, on average, received 3.0 ± 0.9 vaginal injections and a total dose of 1318.4 ± 634.4 IU gonadotropins, resulting in 2.2 ± 1.9 mature oocytes and 1.0 ± 1.2 good embryos. Among these embryos, 0.9 ± 1.0 were transferred to reach a clinical pregnancy rate of 18.1% and a live birth rate of 16.7%. In conclusion, the intermittent vaginal administration of gonadotropins proved to be effective in POR women for their IVF treatments.

Bacterial colonization at caesarean section defects in women of secondary infertility: an observational study.

BACKGROUND: Delayed childbearing has been noted in a high percentage of women with a previous Caesarean section (CS). Many women with CS scar defects (CSDs) present with clinical symptoms of irregular vaginal bleeding. The present study aimed to investigate bacterial colonies at CSDs in women suffering from secondary infertility. METHODS: This observational study included 363 women with secondary infertility who visited the Assisted Reproduction Unit between 2008 and 2013. Among them, 172 women with a previous CS and 191 women with no previous CS were approached. The women with a previous CS had their CS operations in the past 1 to 14 years, with a mean of 3.5 years. The presence of CSDs was detected by vaginal ultrasonography. Bacteriology cultures of specimens taken from the uterine niches in those with CSDs were collected during Day 7 to Day 10 of the follicular phase. Specimens were obtained from the endocervical canal for bacterial culture in those without CSDs. The main outcome measure was the detection of the growth of bacterial colonies. RESULTS: CSDs were found in 60.4% (96 of 159) of women with a previous CS. In women with a previous CS, bacterial colonies were identified in 89.6% (86 of 96) and 69.8% (44 of 63) of women with and without CSDs, respectively. In women with no previous CS, 49.7% (88 out of 177) of bacterial cultures of endocervical samples showed bacterial colony growth. Gram-positive cocci (P = 0.0017, odds ratio (OR) = 1.576, 95% confidence intervals (CI) -22.5 to - 5.4) and Gram-negative rods (P = 0.0016, OR = 1.74, CI - 20.8 to - 5.0) were the most commonly isolated bacteria and contributed to approximately 90% of all microorganisms found in those with a previous CS. In women with a previous CS, more Gram-negative rods were isolated (P = 0.01, OR = 1.765, CI - 27.2 to - 3.8), especially Pseudomonas species (P = 0.02, OR = 1.97, CI - 16.7 to - 1.0), in those with visible CSDs than in those without CSDs. CONCLUSIONS: Bacterial colonization at CSDs was found in a high percentage of women with secondary infertility.

Extended Injection Intervals of Gonadotropins by Intradermal Administration in IVF Treatment.

CONTEXT: Gonadotropins can be administered every 5 days under intradermal injection in in vitro fertilization (IVF) treatment. OBJECTIVE: To explore the effectiveness of intradermal injection of recombinant human FSH (rhFSH) for women undergoing IVF. METHODS: Women who received their first IVF treatment enrolled in this prospective intervention in 2018. All women received a bolus of 900 IU rhFSH intradermally at day 2 of the treatment cycle followed by additional dosage of rhFSH at day 7 and/or day 10. The main outcome measures included the total dose of rhFSH and number of injections required, sequential serum FSH level detected, and number of mature oocytes retrieved. RESULTS: Seventy women completed the study. On average, 2.31 ±â€…0.73 injections and 1662 ±â€…397 IU of rhFSH were administered. While the baseline FSH level was 5.6 ±â€…2.2 IU/L, the serum concentrations of FSH after rhFSH administration were 35.3 ±â€…7.0 on the first day (24 hours) and 10.7 ±â€…3.7 IU/L on the fifth day (120 hours). A total of 10.5 ±â€…6.6 mature oocytes were retrieved, resulting in 7.3 ±â€…5.1 pronuclear embryos; 1.8 ±â€…0.6 embryos were transferred to the uterus. Our findings resulted in 72% fertilization, 91% cleavage, 31% implantation, and 36% live birth rates. Although fewer larger follicles were found, noninferiority results were noted in the mature oocytes retrieved, good embryos available, and clinical pregnancy rate compared with those received conventional daily subcutaneous rhFSH administration. CONCLUSION: Intradermal administration of rhFSH, with a smaller dose of rhFSH and fewer injections, may achieve the goal of a cost-effective and more patient-friendly regimen.

Resumed ovarian function and pregnancy in early menopausal women by whole dimension subcortical ovarian administration of platelet-rich plasma and gonadotropins.

OBJECTIVE: This study was designed to investigate if whole dimension subcortical ovarian administration of platelet-rich plasma with gonadotropin, in proximity to most ovarian follicles, is effective in restoring ovarian functions in women during early menopause. METHODS: Platelet-rich plasma, prepared from 40 mL of autologous peripheral blood using the buffy coat method, was injected into extended subcortical area of bilateral ovaries along with recombinant follicle-stimulating hormone (rFSH) (Gonal-F 300IU) under laparoscopic guidance. The posttreatment ovarian folliculogenesis and serum levels of FSH, luteinizing hormone (LH), and estradiol were followed up for 6 months at weekly to monthly intervals. IVF was carried out in women resuming ovulatory functions. RESULTS: Twelve early menopausal women with mean age of 44.42 ±â€Š2.84 were enrolled. After treatment, 11 women resumed their menstrual period in 37.1 ±â€Š23.5 days. Their average serum FSH was 70.47 ±â€Š20.92 and 26.22 ±â€Š17.55 IU/L, luteinizing hormone was 34.81 ±â€Š11.86 and 14.3 ±â€Š12.8 IU/L, before and after treatment, respectively. The mid-cycle E2 was 251.1 ±â€Š143.8 pg/mL. Ten oocyte retrievals were carried out among six participants, four of them received controlled ovarian stimulation and another two using natural ovulation cycles. Thirteen mature eggs were retrieved which were then ICSI fertilized to obtain 10 normally fertilized 2PN oocytes. Two participants had cleavage stage embryos transferred of which one achieved clinical pregnancy. CONCLUSIONS: Whole dimension subcortical ovarian administration of platelet-rich plasma with gonadotropin was shown to restore ovarian functions, at least temporarily, and could increase the probability of pregnancy using autologous oocytes in women with early menopause.

Structural and functional analysis of Ccr1l1, a Rodentia-restricted eosinophil-selective chemokine receptor homologue.

Mouse Ccr1l1 (Ccr1-like 1) encodes an orphan G-protein-coupled receptor (GPCR) with the highest homology to the inflammatory and highly promiscuous chemokine receptors Ccr1 and Ccr3 (70 and 50% amino acid identity, respectively). Ccr1l1 was first cloned in 1995, yet current knowledge of this putative chemokine receptor is limited to its gene organization and chromosomal localization. Here we report that Ccr1l1 is a Rodentia-specific gene selectively expressed in eosinophils. However, eosinophil phenotypes, development, and responsiveness to chemokines were all normal in naïve Ccr1l1 knockout mice. We demonstrate for the first time that recombinant Ccr1l1 is expressed on the plasma membrane of transfected cells and contains an extracellular N terminus and an intracellular C terminus, consistent with GPCR topology. Using receptor internalization, ß-arrestin recruitment, calcium flux, and chemotaxis assays, we excluded all 37 available mouse chemokines, including Ccr1 ligands, and two viral chemokines as Ccr1l1 ligands, and demonstrated that mouse Ccr1, but not Ccr1l1, exhibits constitutive signaling activity. However, sequence analysis and structural modeling revealed that Ccr1l1 is well equipped to act as a classical signaling GPCR, with N-terminal sulfotyrosines as the only signaling and chemokine-binding determinant absent in Ccr1l1. Hereof, we show that a sulfatable N-terminal Ccr1 Y18 residue is essential for chemotaxis and calcium responses induced by Ccl3 and Ccl9/10, but substituting the corresponding Ccr1l1 F19 residue with tyrosine failed to confer responsiveness to Ccr1 ligands. Although Ccr1l1 remains an extreme outlier in the chemokine receptor family, our study supports that it might respond to unidentified mouse chemokine ligands in eosinophil-driven immune responses.

Live Birth in Woman With Premature Ovarian Insufficiency Receiving Ovarian Administration of Platelet-Rich Plasma (PRP) in Combination With Gonadotropin: A Case Report.

The conception rates among women with premature ovarian insufficiency (POI) remain extremely low. To achieve a successful pregnancy, most of these women have to receive donor oocytes through IVF treatment. Ovarian administration of platelet-rich plasma (PRP) has been recently applied to enhance the ovulatory function in women with poor ovarian response. However, no live birth has been reported for this application in patients with POI. In this study, we present a 37-year-old woman with POI who had secondary amenorrhea for 6 months. The clinical manifestations and evaluation of this women with a diminished ovarian function were an undetectable serum level of AMH (<0.02 ng/mL) and an elevated serum level of FSH (63.65 mIU/mL). A single dose of autologous PRP (extracted from 40 mL of peripheral blood) in combination with gonadotropin (150IU rFSH/75 IU rLH) was directly injected into the stroma of bilateral ovaries via vaginal sonographic guidance. Following the treatment, this patient received controlled ovarian stimulation and IVF during the successive months. Following embryo culture, three cleavage-stage embryos were transferred, leading to a successful pregnancy, which later resulted in the live birth of twins. This case report provides one example of alternative therapy that allows POI patients to use autologous oocytes in IVF treatment.

CB1R antagonist increases hepatic insulin clearance in fat-fed dogs likely via upregulation of liver adiponectin receptors.

The improvement of hepatic insulin sensitivity by the cannabinoid receptor 1 (CB1R) antagonist rimonabant (RIM) has been recently been reported to be due to upregulation of adiponectin. Several studies demonstrated that improvement in insulin clearance accompanies the enhancement of hepatic insulin sensitivity. However, the effects of RIM on hepatic insulin clearance (HIC) have not been fully explored. The aim of this study was to explore the molecular mechanism(s) by which RIM affects HIC, specifically to determine whether upregulation of liver adiponectin receptors (ADRs) and other key genes regulated by adiponectin mediate the effects. To induce insulin resistance in skeletal muscle and liver, dogs were fed a hypercaloric high-fat diet (HFD) for 6 wk. Thereafter, while still maintained on a HFD, animals received RIM (HFD+RIM; n = 11) or placebo (HFD+PL; n = 9) for an additional 16 wk. HIC, calculated as the metabolic clearance rate (MCR), was estimated from the euglycemic-hyperinsulinemic clamp. The HFD+PL group showed a decrease in MCR; in contrast, the HFD+RIM group increased MCR. Consistently, the expression of genes involved in HIC, CEACAM-1 and IDE, as well as gene expression of liver ADRs, were increased in the HFD+RIM group, but not in the HFD+PL group. We also found a positive correlation between CEACAM-1 and the insulin-degrading enzyme IDE with ADRs. Interestingly, expression of liver genes regulated by adiponectin and involved in lipid oxidation were increased in the HFD+RIM group. We conclude that in fat-fed dogs RIM enhances HIC, which appears to be linked to an upregulation of the adiponectin pathway.

High-fat diet-induced insulin resistance does not increase plasma anandamide levels or potentiate anandamide insulinotropic effect in isolated canine islets.

BACKGROUND: Obesity has been associated with elevated plasma anandamide levels. In addition, anandamide has been shown to stimulate insulin secretion in vitro, suggesting that anandamide might be linked to hyperinsulinemia. OBJECTIVE: To determine whether high-fat diet-induced insulin resistance increases anandamide levels and potentiates the insulinotropic effect of anandamide in isolated pancreatic islets. DESIGN AND METHODS: Dogs were fed a high-fat diet (n = 9) for 22 weeks. Abdominal fat depot was quantified by MRI. Insulin sensitivity was assessed by the euglycemic-hyperinsulinemic clamp. Fasting plasma endocannabinoid levels were analyzed by liquid chromatography-mass spectrometry. All metabolic assessments were performed before and after fat diet regimen. At the end of the study, pancreatic islets were isolated prior to euthanasia to test the in vitro effect of anandamide on islet hormones. mRNA expression of cannabinoid receptors was determined in intact islets. The findings in vitro were compared with those from animals fed a control diet (n = 7). RESULTS: Prolonged fat feeding increased abdominal fat content by 81.3±21.6% (mean±S.E.M, P<0.01). In vivo insulin sensitivity decreased by 31.3±12.1% (P<0.05), concomitant with a decrease in plasma 2-arachidonoyl glycerol (from 39.1±5.2 to 15.7±2.0 nmol/L) but not anandamide, oleoyl ethanolamide, linoleoyl ethanolamide, or palmitoyl ethanolamide. In control-diet animals (body weight: 28.8±1.0 kg), islets incubated with anandamide had a higher basal and glucose-stimulated insulin secretion as compared with no treatment. Islets from fat-fed animals (34.5±1.3 kg; P<0.05 versus control) did not exhibit further potentiation of anandamide-induced insulin secretion as compared with control-diet animals. Glucagon but not somatostatin secretion in vitro was also increased in response to anandamide, but there was no difference between groups (P = 0.705). No differences in gene expression of CB1R or CB2R between groups were found. CONCLUSIONS: In canines, high-fat diet-induced insulin resistance does not alter plasma anandamide levels or further potentiate the insulinotropic effect of anandamide in vitro.

Hepatic insulin clearance is the primary determinant of insulin sensitivity in the normal dog.

OBJECTIVE: Insulin resistance is a powerful risk factor for Type 2 diabetes and a constellation of chronic diseases, and is most commonly associated with obesity. We examined if factors other than obesity are more substantial predictors of insulin sensitivity under baseline, nonstimulated conditions. METHODS: Metabolic assessment was performed in healthy dogs (n = 90). Whole-body sensitivity from euglycemic clamps (SICLAMP ) was the primary outcome variable, and was measured independently by IVGTT (n = 36). Adiposity was measured by MRI (n = 90), and glucose-stimulated insulin response was measured from hyperglycemic clamp or IVGTT (n = 86 and 36, respectively). RESULTS: SICLAMP was highly variable (5.9-75.9 dl/min per kg per µU/ml). Despite narrow range of body weight (mean, 28.7 ± 0.3 kg), adiposity varied approximately eight-fold and was inversely correlated with SICLAMP (P < 0.025). SICLAMP was negatively associated with fasting insulin, but most strongly associated with insulin clearance. Clearance was the dominant factor associated with sensitivity (r = 0.53, P < 0.00001), whether calculated from clamp or IVGTT. CONCLUSIONS: These data suggest that insulin clearance contributes substantially to insulin sensitivity, and may be pivotal in understanding the pathogenesis of insulin resistance. We propose the hyperinsulinemia due to reduction in insulin clearance is responsible for insulin resistance secondary to changes in body weight.

CB(1) antagonism restores hepatic insulin sensitivity without normalization of adiposity in diet-induced obese dogs.

The endocannabinoid system is highly implicated in the development of insulin resistance associated with obesity. It has been shown that antagonism of the CB(1) receptor improves insulin sensitivity (S(I)). However, it is unknown whether this improvement is due to the direct effect of CB(1) blockade on peripheral tissues or secondary to decreased fat mass. Here, we examine in the canine dog model the longitudinal changes in S(I) and fat deposition when obesity was induced with a high-fat diet (HFD) and animals were treated with the CB(1) antagonist rimonabant. S(I) was assessed (n = 20) in animals fed a HFD for 6 wk to establish obesity. Thereafter, while HFD was continued for 16 additional weeks, animals were divided into two groups: rimonabant (1.25 mg·kg(-1)·day(-1) RIM; n = 11) and placebo (n = 9). Euglycemic hyperinsulinemic clamps were performed to evaluate changes in insulin resistance and glucose turnover before HFD (week -6) after HFD but before treatment (week 0) and at weeks 2, 6, 12, and 16 of treatment (or placebo) + HFD. Magnetic resonance imaging was performed to determine adiposity- related changes in S(I). Animals developed significant insulin resistance and increased visceral and subcutaneous adiposity after 6 wk of HFD. Treatment with RIM resulted in a modest decrease in total trunk fat with relatively little change in peripheral glucose uptake. However, there was significant improvement in hepatic insulin resistance after only 2 wk of RIM treatment with a concomitant increase in plasma adiponectin levels; both were maintained for the duration of the RIM treatment. CB(1) receptor antagonism appears to have a direct effect on hepatic insulin sensitivity that may be mediated by adiponectin and independent of pronounced reductions in body fat. However, the relatively modest effect on peripheral insulin sensitivity suggests that significant improvements may be secondary to reduced fat mass.

Simplified method to isolate highly pure canine pancreatic islets.

OBJECTIVES: The canine model has been used extensively to improve the human pancreatic islet isolation technique. At the functional level, dog islets show high similarity to human islets and thus can be a helpful tool for islet research. We describe and compare 2 manual isolation methods, M1 (initial) and M2 (modified), and analyze the variables associated with the outcomes, including islet yield, purity, and glucose-stimulated insulin secretion (GSIS). METHODS: Male mongrel dogs were used in the study. M2 (n = 7) included higher collagenase concentration, shorter digestion time, faster shaking speed, colder purification temperature, and higher differential density gradient than M1 (n = 7). RESULTS: Islet yield was similar between methods (3111.0 ± 309.1 and 3155.8 ± 644.5 islets/g, M1 and M2, respectively; P = 0.951). Pancreas weight and purity together were directly associated with the yield (adjusted R(2) = 0.61; P = 0.002). Purity was considerably improved with M2 (96.7% ± 1.2% vs 75.0% ± 6.3%; P = 0.006). M2 improved GSIS (P = 0.021). Independently, digestion time was inversely associated with GSIS. CONCLUSIONS: We describe an isolation method (M2) to obtain a highly pure yield of dog islets with adequate ß-cell glucose responsiveness. The isolation variables associated with the outcomes in our canine model confirm previous reports in other species, including humans.

Large size cells in the visceral adipose depot predict insulin resistance in the canine model.

Adipocyte size plays a key role in the development of insulin resistance. We examined longitudinal changes in adipocyte size and distribution in visceral (VIS) and subcutaneous (SQ) fat during obesity-induced insulin resistance and after treatment with CB-1 receptor antagonist, rimonabant (RIM) in canines. We also examined whether adipocyte size and/or distribution is predictive of insulin resistance. Adipocyte morphology was assessed by direct microscopy and analysis of digital images in previously studied animals 6 weeks after high-fat diet (HFD) and 16 weeks of HFD + placebo (PL; n = 8) or HFD + RIM (1.25 mg/kg/day; n = 11). At 6 weeks, mean adipocyte diameter increased in both depots with a bimodal pattern only in VIS. Sixteen weeks of HFD+PL resulted in four normally distributed cell populations in VIS and a bimodal pattern in SQ. Multilevel mixed-effects linear regression with random-effects model of repeated measures showed that size combined with share of adipocytes >75 µm in VIS only was related to hepatic insulin resistance. VIS adipocytes >75 µm were predictive of whole body and hepatic insulin resistance. In contrast, there was no predictive power of SQ adipocytes >75 µm regarding insulin resistance. RIM prevented the formation of large cells, normalizing to pre-fat status in both depots. The appearance of hypertrophic adipocytes in VIS is a critical predictor of insulin resistance, supporting the deleterious effects of increased VIS adiposity in the pathogenesis of insulin resistance.

Consistency of the disposition index in the face of diet induced insulin resistance: potential role of FFA.

OBJECTIVE: Insulin resistance induces hyperinsulinemic compensation, which in turn maintains almost a constant disposition index. However, the signal that gives rise to the hyperinsulinemic compensation for insulin resistance remains unknown. METHODS: In a dog model of obesity we examined the possibility that potential early-week changes in plasma FFA, glucose, or both could be part of a cascade of signals that lead to compensatory hyperinsulinemia induced by insulin resistance. RESULTS: Hypercaloric high fat feeding in dogs resulted in modest weight gain, and an increase in adipose tissue with no change in the non-adipose tissue size. To compensate for the drop in insulin sensitivity, there was a significant rise in plasma insulin, which can be attributed in part to a decrease in the metabolic clearance rate of insulin and increased insulin secretion. In this study we observed complete compensation for high fat diet induced insulin resistance as measured by the disposition index. The compensatory hyperinsulinemia was coupled with significant changes in plasma FFAs and no change in plasma glucose. CONCLUSIONS: We postulate that early in the development of diet induced insulin resistance, a change in plasma FFAs may directly, through signaling at the level of ß-cell, or indirectly, by decreasing hepatic insulin clearance, result in the observed hyperinsulinemic compensation.

Pulsatile changes in free fatty acids augment hepatic glucose production and preserves peripheral glucose homeostasis.

Recent studies in animal and human models have revealed that free fatty acid (FFA) release from adipose tissue is oscillatory. We have shown in our laboratory that these oscillations are controlled by the sympathetic nervous system (SNS). Although FFAs have been shown to directly stimulate glucose production [endogenous glucose production (EGP)] by the liver and to reduce peripheral glucose utilization, whether the specific pattern of FFA release affects glucose metabolism is unknown. The aim of this study was to examine the effects of pulsatile vs. constant infusion of FFA on glucose homeostasis in the canine model. Euglycemic clamps with basal insulin replacement (0.1 mU.kg(-1).min(-1) insulin) were performed in dogs (n = 8) during infusion of saline (SAL) or the medium-chain fatty acid octanoate, which was given by either pulsatile infusion (PUL: 10 mmol over 2 min every 10 min) or continuous infusion (C-INF: 1 mmol/min) designed to achieve equivalent total FFA mass. Endogenous lipolytic pulses were suppressed with the beta(3)-specific adrenergic receptor antagonist bupranolol. PUL infusion elicited a pulsatile pattern of FFA in circulation with average maximum pulse height of 0.82 +/- 0.04 mM, whereas C-INF FFA levels reached 0.47 +/- 0.03 mM (fasting levels) and were maintained throughout. Glucose uptake was not affected by PUL; however, C-INF significantly reduced glucose uptake compared with both SAL and PUL. Steady-state EGP increased by >90% from basal steady state during PUL but did not change during either SAL or C-INF. Thus, pulsatile FFA infusion led to an increase in EGP while preserving glucose disposal. These data suggest that the pattern of FFA may have a role in regulation of glucose homeostasis, which may have consequences in the obese or insulin-resistant state where the SNS is known to be altered.

Rimonabant prevents additional accumulation of visceral and subcutaneous fat during high-fat feeding in dogs.

We investigated whether rimonabant, a type 1 cannabinoid receptor antagonist, reduces visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) in dogs maintained on a hypercaloric high-fat diet (HHFD). To determine whether energy expenditure contributed to body weight changes, we also calculated resting metabolic rate. Twenty male dogs received either rimonabant (1.25 mg.kg(-1).day(-1), orally; n = 11) or placebo (n = 9) for 16 wk, concomitant with a HHFD. VAT, SAT, and nonfat tissue were measured by magnetic resonance imaging. Resting metabolic rate was assessed by indirect calorimetry. By week 16 of treatment, rimonabant dogs lost 2.5% of their body weight (P = 0.029), whereas in placebo dogs body weight increased by 6.2% (P < 0.001). Rimonabant reduced food intake (P = 0.027), concomitant with a reduction of SAT by 19.5% (P < 0.001). In contrast with the VAT increase with placebo (P < 0.01), VAT did not change with rimonabant. Nonfat tissue remained unchanged in both groups. Body weight loss was not associated with either resting metabolic rate (r(2) = 0.24; P = 0.154) or food intake (r(2) = 0.24; P = 0.166). In conclusion, rimonabant reduced body weight together with a reduction in abdominal fat, mainly because of SAT loss. Body weight changes were not associated with either resting metabolic rate or food intake. The findings provide evidence of a peripheral effect of rimonabant to reduce adiposity and body weight, possibly through a direct effect on adipose tissue.