Effects of feeding pattern on ghrelin and insulin secretion in pigs

Ghrelin is a peptide hormone that has been implicated in the regulation of feed intake, but little is known about its secretion in pigs. Hence, the effect of feeding pattern on the regulation of ghrelin secretion was tested. In experiment 1, barrows were allotted randomly into 1 of 2 groups, (1) ad libitum fed (CONT) and (2) limited access to feed (once per day, MEAL). Blood samples were taken through jugular catheters every 15 min for 6 h after 7 d on the experimental feeding regimen. Plasma concentrations of ghrelin and insulin were determined by radioimmunoassay. Ghrelin concentrations in the MEAL pigs were elevated before feeding and declined after feeding (P < 0.01). No pattern in plasma ghrelin concentrations was observed in the CONT pigs, but ghrelin concentrations were lower than in the MEAL group. Insulin concentrations were greater in CONT pigs (P < 0.01) during most of the sampling and increased after feeding in the MEAL pigs (P < 0.01). In experiment 2, the treatments were the same as in experiment 1; however, the amount of feed was increased in the MEAL group so that their daily intake was similar to the CONT pigs. Ghrelin concentrations in the MEAL group were again elevated before the meal and declined afterward (P < 0.01). Insulin but not glucose concentrations were negatively correlated with ghrelin. Once-per-day feeding resulted in increased plasma concentrations of ghrelin, which decreased after feeding. Ghrelin may be involved in the regulation of feed intake in pigs.

p16 expression in psoriatic lesions following therapy with propylthiouracil, an antithyroid thioureylene

Plaque formation is a characteristic finding in patients with psoriasis and reflects cytokine-induced keratinocyte proliferation and/or impaired apoptosis of keratinocytes. Antithyroid thioureylenes such as propylthiouracil (PTU) and methimazole (MMI) are effective in the treatment of plaque psoriasis. Following PTU and MMI treatment, proliferative cell nuclear antigen (PCNA) expression is significantly reduced, suggesting that these medications have an antiproliferative effect. p16 is an antiapoptotic protein that is present in relative abundance in psoriatic plaques and is believed to play a potential role in the persistent senescence and impaired apoptosis of the keratinocytes in the plaque. This study examined p16 expression in biopsy samples of eight patients with plaque psoriasis given 300 mg of propylthiouracil in divided doses for 3 months. Despite significant clinical and histological improvement with PTU treatment, p16 expression was essentially unchanged, suggesting that the beneficial effect of PTU in psoriasis is not mediated through a decrease in p16 expression. The effect of PTU on other antiapoptotic proteins such as bcl-xL remains to be determined.

Leptin and IGF-I levels in unconditioned male volunteers after short-term exercise

We have previously shown that serum gonadotropins, particularly LH, decline after acute exercise in male volunteers. The mechanism for this decline is unknown. Plasma leptin and IGF-I concentrations were measured in seven male volunteers after acute exercise to exhaustion using the Bruce protocol. Leptin concentrations declined following exercise reaching nadir values 30-120 min after exercise. As anticipated, plasma IGF-I concentrations showed a transient rise immediately after exercise falling thereafter to nadir levels 60-90 min after exercise before returning towards baseline levels. In view of the previously described decline in gonadotropin release after acute exercise, the decline in plasma leptin levels, perhaps related to the rise in IGF-I, may play a role in exercise-induced inhibition of gonadotropin release presumably by inhibition of GnRH secretion.

Ketosis with enhanced GABAergic tone promotes physiological changes in transcendental meditation

Transcendental meditation (TM) is a stylized form of physical and mental relaxation which is associated with changes in the secretion and release of several pituitary hormones. The hormonal changes induced by TM mimic the effects of the inhibitory neurotransmitter gamma aminobutyric acid (GABA). It is hypothesized that TM produces changes in pituitary hormone secretion by enhancing hypothalamic GABAergic tone as a result of TM associated ketosis. Ketosis enhances the entry of glutamate, the amino acid substrate of GABA into synaptosomes, making more glutamate available for conversion to GABA through the glutamate decarboxylase pathway.

Effects of adenosine infusion on renal function, plasma ANP and ADH concentrations and central hemodynamics in anesthetized pigs

1. The effect of high-dose adenosine administration on atrial natriuretic peptide (ANP) and antidiuretic hormone (ADH) release is not completely understood, and data concerning the effect of adenosine on renal and systemic hemodynamics in the pig are lacking. Measurements of central hemodynamics, renal blood flow and urine production were made in anesthetized pigs during infusion of adenosine. The relationship between these parameters and the plasma concentrations of ANP, ADH and renal renin production was examined. 2. Adenosine infusion at the rate of 140 mg/kg per minute resulted in a significant decrease in systolic, diastolic and mean arterial blood pressure as well as pulmonary arterial pressure. However, cardiac output and renal blood flow remained unchanged during adenosine infusion. Likewise, heart rate remained unchanged until the end of infusion when it increased significantly, Plasma ANP and ADH concentrations increased significantly within 30 min after adenosine infusion, reaching peak levels at 30 to 60 min. However, despite the significant decrease in arterial blood pressure, renal renin production did not change significantly. 3. The adenosine-induced rise in ANP, which is normally released by atrial stretch, may represent a direct effect of adenosine on the cardiac myocytes. The increase in ADH may be a result of decreased arterial blood pressure triggering stimulatory signals from the aortic arch and carotid body receptors to hypothalamic-pituitary sites of ADH production/release. Urine flow decreased dramatically within 30 min of adenosine infusion. Thus adenosine infusion at the given rate led to marked reduction in systemic and pulmonary arterial pressures without significant change in cardiac output, heart rate and renal blood flow. This was associated with a marked increase in plasma ANP and ADH levels with no significant change in renal renin production despite a marked reduction in arterial blood pressure. 4. Maintenance of renal blood flow despite marked reduction in perfusion pressure suggests that, at high doses, adenosine induces renal vasodilation in pigs as opposed to a combined afferent and efferent vasoconstriction known to occur under different experimental conditions.

Effects of blood pH and blood lactate on growth hormone, prolactin, and gonadotropin release after acute exercise in male volunteers

It has recently been found that prevention of the acidosis of anaerobic exercise blocks beta-endorphin release. Because heavy exercise affects secretion of other anterior pituitary hormones, we studied the results of alkali infusion and ingestion upon blood levels of four hormones: luteinizing hormone (LH), follicle-stimulating hormone (FSH), growth hormone (GH), and prolactin (PRL). Eight male subjects were studied after either 2 mEq/kg placebo (NaCl) or alkali (NaHCO3) administered before and during exercise to exhaustion. Blood samples were obtained before exercise and then 15, 30, 60, 90, 120, and 180 min postexercise. GH and PRL but not FSH or LH increased significantly postexercise, with a peak at 60 min, and subsequently declined back to baseline by 180 min. Base treatment reduced GH at baseline and postexercise (except at 60 min) and increased PRL significantly, particularly at 60 min. While the precise mechanisms on how acid/base changes affect hormone release remain to be defined, there are possible consequences on gonadal function and substrate availability during exercise.

Serum levels of androstenedione, testosterone and dehydroepiandrosterone sulfate in patients with premature ovarian failure to age-matched menstruating controls

Serum concentrations of androstenedione, testosterone and dehydroepiandrosterone sulfate (DHEAS) were measured in 29 patients with premature ovarian failure (POF) and an identical number of age-matched normal control subjects. The study was aimed at determining possible differences in androgen concentrations of ovarian and adrenal origin in POF patients and age-matched normal menstruating controls. Serum testosterone and DHEAS concentrations in the 2 populations were not significantly different. The serum androstenedione concentration in the POF patient group (3,077.50 +/- 1,122.33 pmol/l) was significantly lower than in age-matched normal control subjects (4,167.70 +/- 1,381.09 pmol/l, p < 0.005), possibly reflecting the loss of ovarian androstenedione secretion and/or a subtle defect in adrenal steroidogenic capacity.

Relationship between prorenin, IGF-I, IGF-binding proteins and retinopathy in diabetic patients

Plasma prorenin and renin, serum insulin-like growth factor I (IGF-I) and IGF-binding protein (IGFBP-2 and IGFBP-3) concentrations were measured in 22 randomly selected male and female patients with insulin-dependent diabetes mellitus (IDDM) or non-IDDM (NIDDM). Plasma prorenin concentration was significantly elevated in patients with proliferative retinopathy (1869.5 +/- 785.0 mUL-1, mean +/- SEM) compared to patients with nonproliferative retinopathy (325.5 +/- 73.2 mUL-1, P < 0.003) and those without retinopathy (318.6 +/- 47.3 mUL-1, P < 0.007). Similarly, serum insulin-like growth factor-I (IGF-I) concentration in patients with proliferative retinopathy (126.3 +/- 21.5 micrograms L-1) was significantly higher than in patients with nonproliferative retinopathy (126.3 +/- 14.85 micrograms L-1, P < 0.004) and without retinopathy (135.2 +/- 37.26, P < 0.05). There was moderately strong positive correlation between plasma prorenin and serum IGF-I concentrations (r = 0.56, P < 0.01). Plasma prorenin concentration was uninfluenced by change in renal function (creatinine clearance, serum creatinine or BUN), but IGF-I levels were inversely related to creatinine clearance (r = 0.67, P < 0.002). There was no demonstrable relationship between IGF-binding proteins and prorenin or renin concentrations. In view of some overlap between plasma prorenin and serum IGF-I concentrations in diabetic patients with proliferative and nonproliferative retinopathy, measurement of both markers may be more useful in predicting the development of proliferative retinopathy in patients with diabetes mellitus than either measurement alone.

Relationship between serum estradiol concentration and IGF-I, IGF-II and IGF-binding proteins in patients with premature ovarian failure on short-term estradiol therapy

OBJECTIVE

Insulin-like growth factors (IGFs) exert stimulatory effects on follicular growth and development, and early embryogenesis. In view of this, we studied the effect of short-term estradiol treatment, as used in preparing the uterus for embryo implantation, on the serum concentrations of IGFs and their binding proteins (IGFBP) in patients with premature ovarian failure (POF).

PATIENTS AND METHODS

Twenty-four patients with POF, enrolled in an assisted reproduction program, were treated with increasing doses of estradiol up to 8 mg daily for 6 weeks. Blood was sampled for measurement of serum estradiol, IGF-I, IGF-II, and IGFBP 1, 2 and 3 at various times during estradiol treatment.

RESULTS

There was no significant correlation between serum estradiol concentrations and the serum concentrations of IGF-I and IGF-II. As expected, IGF-I and IGF-II concentrations in serum correlated positively with the serum concentration of IGFBP-3, the major IGF-binding protein in serum.

CONCLUSION

The results of this study suggest that estradiol therapy as used to prepare the uterus for implantation has no significant effect on serum IGF-I and IGF-II concentrations, and therefore probably does not influence, via an IGF-mediated mechanism, the success of implantation and early embryonic development.

Effect of orally administered antithyroid thioureylenes on PCNA and P53 expression in psoriatic lesions

BACKGROUND

Antithyroid thioureylenes are effective agents in the oral and topical treatment of patients with chronic plaque psoriasis.

METHOD

The effect of oral treatment with 6-n-propyl 2-thiouracil (propylthiouracil, PTU) and 2-mercapto 1-methyl imidazole (methimazole, MMI) on proliferating cell nuclear antigen (PCNA), and p53 protein expression was studied in patients with stable plaque psoriasis.

RESULTS

Following treatment with PTU and MMI, PCNA staining in psoriatic epidermis was significantly decreased. P53 was minimally expressed in untreated lesions, and treatment with PTU and MMI did not enhance p53 expression in the psoriatic lesions.

CONCLUSIONS

Since PCNA is a marker of cellular proliferation and p53 inhibits cellular cycling, some of the beneficial effects of PTU and MMI in psoriasis may depend on the ability of the drugs to impair cellular turnover, perhaps by binding to the triiodothyronine (T3) receptor. These effects may be in addition to the previously described effects of PTU and MMI as immune modulators and free radical scavengers.

Serum hormonal concentrations following transcendental meditation--potential role of gamma aminobutyric acid

Transcendental mediation (TM) is a stylized form of physical and mental relaxation which is associated with changes in the secretion and release of several pituitary hormones. The hormonal changes induced by TM mimic the effects of the inhibitory neurotransmitter gamma aminobutyric acid (GABA). It is hypothesized that TM produces changes in pituitary hormone secretion by enhancing hypothalamic GABAergic tone, and its anxiolytic effects by promoting GABAergic tone in specific areas of the brain. This mechanism is similar to the effects of synthetic anxiolytic and tranquilizing agents such as benzodiazepines that bind to components of the GABA-A (GABAA) receptor. TM, therefore, may produce relaxation by enhancing the effects of an endogenous neurotransmitter analogous to the effects of endorphins in runners who reportedly experience a 'runner's high'.

A controlled trial of topical propylthiouracil in the treatment of patients with psoriasis

BACKGROUND

Propylthiouracil (PTU, 6-n-propyl 2-thiouracil) is an antithyroid thioureylene, which, in addition to its ability to decrease thyroid hormone synthesis, also has immune modulatory and free radical scavenging abilities. We have previously shown that oral PTU and another antithyroid thioureylene are effective in the treatment of plaque psoriasis.

OBJECTIVE

The current study was performed to determine the efficacy of topical PTU in psoriasis.

METHODS

Topical PTU and placebo were administered, in a double-blind fashion, three times daily for 4 to 8 weeks to nine volunteers with long-standing plaque psoriasis. The patients had biopsy specimens of their lesions taken at the start and end of the study. Clinical response was monitored with a scoring system based on scale, erythema, and thickness of the plaques. Complete blood cell count and thyroid function studies were obtained in each patient at the beginning and at 2-week intervals thereafter until completion of the study.

RESULTS

Topically applied PTU produced significant clearing of the lesions (clinical scores 8.0 +/- 0.6 vs 3.7 +/- 0.3, p < 0.0001 at 4 weeks, and 4.0 +/- 0.6, p < 0.02 at 8 weeks); two patients demonstrated nearly complete clearing. Placebo-treated and untreated "control" areas showed no significant change during the study. None of the subjects had hypothyroidism or cytopenia.

CONCLUSION

Topical applied PTU is effective in the treatment of patients with stable plaque psoriasis and has low toxicity.

Serum ICAM-1 concentrations in patients with psoriasis treated with antithyroid thioureylenes

Serum concentrations of intercellular adhesion molecule-1 (ICAM-1), a marker of early T-cell activation were measured in 14 patients with stable plaque psoriasis who received treatment for 8 weeks with the antithyroid thioureylenes, propylthiouracil (PTU) or methimazole (MMI) which have been previously shown to produce significant improvement in such patients. Baseline serum concentrations of ICAM-1 were significantly higher in the patients with psoriasis compared with normal control volunteers. Following therapy with either PTU (300 mg daily) or MMI (40 mg daily) serum ICAM-1 concentrations did not decline significantly. Since ICAM-1 expression on vascular endothelium increases in active psoriasis, and is postulated to promote T-cell migration to and retention at these sites, it is hypothesized that the beneficial therapeutic effects of thioureylenes in psoriasis occur distal to the events that lead to lymphocyte migration to vascular structures in the dermis.

Exercise and gonadal function

Exercise is associated with release of a number of pituitary and hypothalamic hormones and a decline in the concentration of luteinizing hormone (LH). Follicle stimulating hormone (FSH) is generally not influenced by exercise. Serum inhibin concentrations, which are reciprocally influenced by serum FSH concentrations, are increased in some animals but are unchanged after acute exercise in human males. Teleologically, the decline in gonadotrophic hormone (LH) secretion after exercise may be geared to enhance individual survival over species propagation in times of stress, analogous to the postulated 'fight or flight' reaction. The decrease in gonadotrophic hormone (LH) secretion is believed to be due to changes in gonadotrophin releasing hormone (GnRH) pulse frequency and amplitude, particularly in women, who often develop amenorrhoea. Males have less dramatic changes in their hypothalamic-pituitary-gonadal axis, although a significant decrease in serum testosterone in physically conditioned males can usually be demonstrated. In this update possible mechanisms for the decline in gonadotrophin secretion with exercise are briefly discussed.

Effect of propylthiouracil and methimazole on serum levels of interleukin-2 receptors in patients with psoriasis

BACKGROUND

We have previously reported clinical improvement in patients with psoriasis who received orally administered antithyroid thioureylenes, propylthiouracil (PTU), and methimazole (MMI). The antithyroid drugs are believed to exert immunomodulatory effects based on the results of studies in patients with Graves' disease, the only disease in which they are clinically used. The potential of these drugs to mediate clinical improvement in patients with psoriasis by reducing expression of the interleukin-2 receptor (IL2R), a marker of early T and B cell activation, was addressed in the present study.

METHODS

Baseline serum concentrations of IL2R were measured by an enzyme-linked immunosorbant assay (ELISA) in 15 patients with stable plaque psoriasis and in the same patients after 8 weeks of oral therapy with either 300 mg of propylthiouracil (n = 7) or 40 mg methimazole (n = 8) given daily. Baseline values were compared with normal controls.

RESULTS

Serum IL2R concentrations in the psoriatic patients were significantly higher than in normal controls. After treatment with PTU or MMI, IL2R serum concentrations were not significantly reduced either in the group as a whole or separately in the PTU and MMI treated patients.

CONCLUSIONS

Since elevated serum concentrations of IL2R often reflect T and B cell activation, and elevated IL2R serum levels are seen in several autoimmune diseases, it is speculated that the beneficial effect of thioureylenes in patients with psoriasis is mediated by some mechanism(s) other than reduction of IL2R expression in activated lymphocytes.

Propylthiouracil in psoriasis: results of an open trial

BACKGROUND

Propylthiouracil (PTU) is an antithyroid thioureylene that has immune modulatory and free radical scavenging abilities. In view of the immunomodulatory effects of PTU, we decided to study the therapeutic response of patients with psoriasis to oral PTU.

OBJECTIVE

Our purpose was to study the effect of oral PTU in patients with stable plaque psoriasis.

METHODS

Oral PTU, 100 mg, was administered every 8 hours for 8 weeks to 10 patients with long-standing psoriasis. Skin biopsy specimens were taken from the lesions before and at the end of the study. Clinical response was monitored with the Psoriasis Area and Severity Index scoring system. Histologic scores were graded with a 5-point grading scale. Complete blood cell count was obtained at the beginning and at the end of the study. Thyroid-stimulating hormone (TSH) was obtained at the beginning and every 2 weeks thereafter until completion of the study.

RESULTS

Three patients dropped out of the study. Of the remaining seven, two showed near-complete resolution of their psoriatic lesions, whereas the remainder showed moderate improvement in their clinical scores. Histologic scores were significantly improved in the group with all but one patient showing improvement or no change. Thyroid function tests were unchanged in all but one patient who showed a slight increase in serum TSH at the sixth week of therapy.

CONCLUSION

Because of its low toxicity relative to other oral treatments of psoriasis, PTU may have a role in the treatment of patients with this disorder.

Melatonin and gonadotropin secretion after acute exercise in physically active males

Serum concentrations of luteinizing hormone (LH), follicle stimulating hormone, testosterone (T) and melatonin were measured in seven physically active male volunteers after exercise on a treadmill using the Bruce protocol. Measurements were made on blood samples obtained before exercise, within 30 s after exercise, at 15 min after exercise, and subsequently at 30-min intervals after exercise for a total duration of 180 min. Serum LH concentration fell from a peak post-exercise level of 15.7 (4.7) IU.l-1 [mean (SD)] to a nadir of 10.3 (2.4) IU.l-1 (P < 0.004). Nadir values in individual volunteers were seen between 60 and 150 min after exercise. This fall in serum LH was paralleled by a similar fall in the concentration of serum T. Serum melatonin concentrations did not change significantly after exercise. It is concluded that melatonin, despite is reported anti-gonadotropic properties, does not play a role in the depression of serum LH after acute strenuous exercise in physically active males.

Methimazole (2-mercapto 1-methyl imidazole) in psoriasis--results of an open trial

Methimazole, an antithyroid drug, was orally administered, in an open trial, in a dose of 20 mg every 12 h for 8 weeks to 8 volunteers with long-standing psoriasis. 3-mm punch biopsies were taken from the lesions at the start and at the end of the study. Clinical response was assessed using the Psoriasis Areas Severity Index score. Methimazole produced marked to moderate improvement in the clinical scores in the majority of patients. Histological scores were also significantly improved in all patients. Unexpectedly, thyroid function tests were not affected by methimazole therapy in all but one patient, and none of the patients developed drug-induced cytopenia. Methimazole may be an effective therapeutic agent in the management of psoriasis; it most probably exerts its therapeutic effect by acting on the immune system.

The pituitary-gonadal axis in experimental nephrotic syndrome in male rats

Basal and luteinizing releasing hormone-stimulated gonadotropin secretion were studied in male rats made nephrotic with puromycin, and in pair-fed and normal control animals. In addition, plasma concentrations of testosterone, androstenedione, estradiol, and estrone were measured in the three groups of animals. Urinary testosterone concentrations were also measured in the three experimental groups. The data showed that basal luteinizing hormone concentration was significantly elevated in the nephrotic group compared with the pair-fed and normal control groups. Gonadotropin response to luteinizing releasing hormone stimulation was not significantly different in the three groups, suggesting an intact hypothalamic-pituitary axis in nephrotic syndrome. Urinary testosterone concentration in the nephrotic animals was significantly higher than in the pair-fed and normal control groups. Plasma testosterone, androstenedione, estradiol, and estrone concentrations were significantly lower in the nephrotic and pair-fed animals than in the normal control animals, indicating possibly impaired gonadal steroidogenesis in these two groups that may be related to the catabolic state of the animals. It thus appears that urinary loss of protein-bound (sex hormone binding globulin-bound) testosterone in the nephrotic syndrome leads to increased basal secretion of luteinizing hormone, presumably as a result of increased luteinizing releasing hormone secretion. This occurs to compensate for the abnormal urinary testosterone loss and is an attempt to restore plasma testosterone concentrations to normal. The higher basal plasma luteinizing hormone concentration in the nephrotic group supports this conclusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Are all males equal? Anatomic and functional basis for sexual orientation in males

In non-human primates anterior hypothalamic nuclei are closely involved in heterosexual activity in males. In humans, hypothalamic nuclei which correspond to these nuclei in non-human primates have been shown to have a neuronal density in homosexual men that is approximately half of that seen in heterosexual men. In addition, homosexual men exhibit a positive luteinizing hormone response to acutely administered estrogen that is intermediate between women (flat response) and heterosexual men (exaggerated response). Furthermore, on the basis of serum testosterone concentrations in similarly feminized transsexual males on estrogen/progestogen treatment 3 distinct groups can be identified. It is postulated that anatomic differences in the anterior hypothalamic nuclei that regulate sexual orientation in males may lead to alteration in the gonadotropin releasing hormone (GnRH) pulse/frequency leading to a more female-type pattern of gonadotropin secretion in homosexual males. Based on data in transsexual males this pattern may be more or less of the female-type in subsets of male homosexuals.

Immobilization osteoporosis in paraplegia

The pathophysiology of osteoporosis as it relates to immobilization or disuse osteoporosis in paraplegics is briefly reviewed. The physiology of bone formation and resorption is discussed, and the influence of piezoelectric forces on bone integrity and the consequences of the loss of this effect in paraplegics is addressed. When bone is stressed, negative charges accumulate on the side from which the stress is applied and positive charges accumulate on the opposite side. Presumably the collagenous component of bone plays the major role in the generation of electrical potentials. Another mechanism important in the generation of electrical potentials is created by liquid planes streaming past solid planes. Diminished forces acting on bone, as in paraplegia, are translated into changes in the activity of bone remodeling units which can be assessed by histomorphic and histoenzymatic techniques. Other biochemical and endocrine consequences of immobilization involve increased serum calcium, decreased serum parathyroid hormone (PTH), and decreased dihydroxy-vitamin D synthesis. Urinary hydroxyproline and calcium excretion are increased, as is stool calcium. The bone loss that follows immobilization may produce an increased susceptibility to fractures involving long bones more than the spinal column, and is due more to decreased bone formation than to accelerated bone resorption. The treatment of immobilization osteoporosis primarily involves early remobilization, but other treatments, including the use of electrical fields and the administration of bisphosphonates, calcitonin, and a growth hormone are being actively investigated.

Hormone pattern in pharmacologically feminized male transsexuals in the California State prison system

The hormonal profile of 40 transsexual inmates from a pool of 86 inmates in the California State prison system was studied before and after therapy with feminizing hormones. Clinical and social data were obtained on all 86 inmates; the incidence of human immunodeficiency virus (HIV) seropositivity was examined in 76 of the 86 individuals. Despite similar degrees of feminization in all 40 individuals in whom hormonal studies were performed, variable suppression of serum testosterone concentrations was present. Based on their testosterone concentrations while on feminizing hormone therapy, the transsexual inmates could be divided into three groups. In Group I (the "suppressed" group), the serum testosterone concentrations were markedly depressed (less than 10 ng/dL); in Group II (the "non-suppressed" group), the values of testosterone were normal (446 to 1072 ng/dL); and in Group III (the "intermediate" group), the testosterone values were between those of the suppressed group and the nonsuppressed group. We speculate that feminizing hormone therapy may induce the development of a state of target hormone resistance to testosterone that results in similar degrees of feminization independent of the circulating concentrations of testosterone. The incidence of HIV seropositivity (3/76) was considerably less than anticipated based on previous studies in populations at high risk for developing the acquired immunodeficiency syndrome.

The endocrinology and pathophysiology of alcoholic cirrhosis and functional renal failure--a review

The pathophysiology and characteristics of decompensated alcoholic cirrhosis and functional renal failure are reviewed. The review will be restricted to alcoholic cirrhosis, because most cases of functional renal failure in the United States occur in the setting of alcoholic cirrhosis, which is also the most common cause of ascites in North America and Europe. Moreover, hepatorenal syndrome may complicate other forms of liver disease besides alcoholic cirrhosis, but the pathogenesis in such circumstances may not be the same as in the cirrhotic state.

Effective portal insulin delivery with enzyme-protected capsules in pancreatectomized pigs

1. Plasma concentrations of insulin, C-peptide, glucagon and glucose were measured in surgically pancreatectomized pigs given insulin into the colon directly and in enteric peptidase-resistant (methacrylic acid copolymer-encapsulated) form. 2. Following introduction of insulin-containing capsules, plasma insulin concentration rose from 2.7 +/- 0.1 microU/ml to 110.9 +/- 51.9 microU/ml in the portal vein, and from 2.6 +/- 0.1 microU/ml to 26.9 +/- 7.3 microU/ml in the systemic circulation. Corresponding portal and systemic values after direct (non-encapsulated) insulin instillation were 28.2 +/- 15.9 microU/ml to 44.8 +/- 13.0 microU/ml and 7.5 +/- 2.6 microU/ml to 15.2 +/- 2.5 microU/ml respectively. Insulin concentrations peaked at 75 min in the group as a whole and between 60-90 min in individual animals. Absorption was most pronounced in pigs given aprotinin (a trypsin inhibitor) with insulin. 3. Plasma portal vein glucose concentrations fell from 76.2 +/- 8.9 mg/dl to 31.1 +/- 3.2 mg/dl 150 min after encapsulated insulin administration. Corresponding systemic glucose levels were 84.5 +/- 11.0 mg/dl and 37.0 +/- 1.4 mg/dl. 4. Colonic administration of insulin in methacrylic acid coated capsules results in peak portal and systemic insulin levels 60-90 min after administration. Co-administration of aprotinin enhances the fraction of insulin absorbed.

Inhibin and gonadotrophin secretion in physically active males after acute exercise

Serum concentrations of luteinizing hormone (LH) follicle stimulating hormone (FSH), testosterone and inhibin were measured in six physically active male volunteers after heavy exercise on a treadmill. Hormone measurements were made before exercise, immediately after exercise and at 30-min intervals for 3 h after exercise. Serum concentrations of LH fell after exercise reaching nadir values between 60 and 180 min post-exercise. The nadir value of LH for the group as a whole occurred 90 min after exercise. Serum testosterone concentrations paralleled the changes in LH concentrations. Serum FSH and inhibin concentrations did not show any appreciable change from baseline values. The data suggest that acute exercise does not significantly lower serum concentrations of FSH or inhibin. Whether repetitive and prolonged heavy exercise, as in competitive runners, produces alterations in serum inhibin concentrations remains to be determined.

Corticotropin releasing hormone and gonadotropin secretion in physically active males after acute exercise

Plasma concentrations of corticotropin releasing hormone (CRH) and the serum concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone, adrenocorticotropic hormone (ACTH) and cortisol were measured in seven physically active males after acute exercise on a treadmill using the Bruce protocol. Measurements were made in the basal pre-exercise state, immediately after exercise, and at 30-min intervals for 3 h after exercise. Serum LH concentrations declined following exercise reaching nadir values between 60 and 180 min after exercise (90 min post exercise in the group). The nadir values in individual volunteers were significantly lower than both the baseline and post-exercise levels. This fall in serum LH concentration appeared to follow a slight but significant elevation of the plasma concentration of CRH which reached peak levels when measured immediately post exercise. Plasma ACTH concentrations paralleled the rise in CRH, but fell to undetectable levels of below 13.8 nmol.l-1 (less than 5 ng.l-1) 60 min after exercise. Plasma cortisol concentrations peaked approximately 30 min after the rise in ACTH, after which they gradually declined to baseline levels. Plasma testosterone concentrations paralleled the concentrations of LH. The data suggest that CRH, on the basis of its previously described gonadotropin-depressant property, may be the hormone involved in the exercise-mediated decline in serum LH. Alternatively, some as yet unidentified factor(s), may be involved in producing the altered concentrations of both LH and CRH.

Hypothesis: insulin is responsible for the vascular complications of diabetes

It is proposed that the systemic hyperinsulinemia and hepatic portal hypoinsulinemia that occurs with conventional injectable preparations of insulin currently used in the treatment of patients with diabetes mellitus is largely responsible for the morbidity associated with this disease. Epidemiological evidence and animal experimentation strongly support systemic hyperinsulinemia as a major factor in genesis of atherosclerosis in diabetic patients. In addition, in vitro studies demonstrate a direct effect of insulin on endothelial cell and arterial smooth muscle proliferation. On the other hand, inadequate hepatic delivery of insulin is associated with overproduction of renal vasoregulatory factors leading to glomerular hyperfiltration and ultimately to glomerulosclerosis and its clinical endpoint--end-stage renal disease. In the absence of widespread success of pancreatic and islet-cell transplantation as a means to deliver insulin physiologically into the hepatic portal circulation, methods must be devised and perfected to accomplish such delivery using approaches such as orally administering insulin in intestinal-enzyme protected capsules. Until such methods of delivery are available for safe and widespread use, one should abandon the illusory goal of rigid glucose control in favor of methods that reduce insulin requirement. Along these lines, dietary restriction and aerobic exercise should be the major life style changes advised for diabetic patients. Reduction of glomerular hyperfiltration in diabetic patients can be promoted with the use of low protein diets and/or angiotensin converting enzyme inhibitors.

Glomerulopressin activity in carbon tetrachloride-induced cirrhosis in male rats

The activity of glomerulopressin, a putative renal vasoregulatory hormone that is synthesized in the liver, was assayed in male rats with carbon tetrachloride-induced cirrhosis and the results were compared to glomerulopressin activity in normal-control and pair-fed animals. Glomerulopressin activity in blood samples collected from the hepatic vein of the cirrhotic group was significantly lower than the activity in the normal-control and pair-fed groups. Glomerulopressin activity in the normal-control and the pair-fed groups were not significantly different. The data support the concept that glomerulopressin deficiency in liver disease, such as cirrhosis, may play a role in the genesis of the functional renal failure associated with liver disease.

Insulin and C-peptide levels following oral administration of insulin in intestinal-enzyme protected capsules

1. Crystalline beef insulin was administered orally in capsules composed of a methacrylic acid copolymer which prevented breakdown of the insulin by enteric and pancreatic peptidases. 2. In studies performed in 3 individuals blood was sampled before oral ingestion of the insulin (40 144 units), and at 15 or 30 min intervals thereafter for 5.5 hr for measurement of immunoreactive insulin and C-peptide concentrations. 3. Following the administration of oral insulin, plasma immunoreactive insulin concentrations became elevated 4-5 hr after ingestion. 4. The rise in plasma insulin concentrations was associated with a corresponding fall in the concentration of C-peptide. 5. The data suggest that this preparation of oral insulin can produce significant enteric absorption of the peptide, and that further investigation of agents that facilitate insulin absorption from the gut might render the use of methacrylic acid copolymer coated capsules a physiologically sound and a commercially feasible method of oral insulin administration.

Male hypogonadism due to nontumorous hyperestrogenism

Male hypogonadism due to the nontumorous production of estrogen was studied in a patient with gynecomastia and bilateral small testicles. Both the gynecomastia and the decrease in testicular size developed in the 5-year period before presentation. Peripheral serum concentrations of testosterone were in the low to low-normal range, while those of 17 beta-estradiol (E2) were significantly elevated, as were the urinary concentrations of total estrogen. Steroid hormone concentrations were measured in the left and right spermatic veins and the left and right adrenal veins in the basal state, and after stimulation with GnRH and ACTH. Spermatic vein concentrations of E2 were 3 to 20 times higher than concentrations previously reported in normal males. Spermatic vein concentrations of testosterone were normal. The spermatic vein concentrations of androstenedione were approximately three times higher than the mean concentration of androstenedione previously reported in the spermatic vein of normal males. The concentrations of E2 and androstenedione in the adrenal veins were also significantly elevated when compared to the concentrations previously reported in normal subjects. The authors postulate that the hyperestrogenism in this patient was due to increased aromatization of the precursor substrates, testosterone in the testes, and androstenedione in the adrenals to E2 and E1 in the testes and adrenals, respectively. Alternatively, an increased abundance or activity of the 17 beta-hydroxysteroid dehydrogenase isoenzyme which converts estrone (E1) to E2 or a relative deficiency of the 17 beta-hydroxysteroid dehydrogenase isoenzyme, which converts androstenedione to testosterone, could theoretically account for the reported abnormalities.

Glucose intolerance in renal failure: role of endogenous opioids

Plasma concentrations of glucose, insulin, and beta-endorphin/beta-lipotropin were measured in male Sprague-Dawley rats with experimental renal failure after intravenous glucose challenge in the presence and absence of opioid blockade with intravenously administered naloxone. The results were compared with those obtained in sham-operated normal control and pair-fed groups of animals. Baseline glucose concentrations were similar in the three groups of animals. Plasma baseline insulin concentrations were significantly lower in the rats with renal failure and the pair-fed animals compared with the normal controls. After glucose challenge the renal failure group demonstrated glucose intolerance, which was not improved after naloxone treatment given 15 minutes before glucose challenge. Peak insulin levels after glucose challenge in the renal failure and pair-fed groups increased significantly after naloxone administration. Interestingly, circulating concentrations of plasma beta-endorphin/beta-lipotropin were not significantly different in the three groups of animals when measured either in the baseline state or after glucose challenge. The data indicate that the carbohydrate intolerance in experimental renal failure may be partly due to an increase in pancreatic islet opioidergic tone, because an improvement in insulin secretion was demonstrated in the absence of any change in circulating beta-endorphin/beta-lipotropin concentrations after naloxone. The failure to demonstrate any improvement in glucose disposal after naloxone, despite the augmented secretion of insulin after naloxone in the animals with renal failure, points to peripheral resistance to the effects of insulin that is not influenced by opioid blockade.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial natriuretic peptide, arginine vasopressin, aldosterone and plasma renin activity in carbon tetrachloride-induced cirrhosis in rats

The concentrations of atrial natriuretic peptide, arginine vasopressin, aldosterone and the plasma renin activity were studied in male rats with carbon tetrachloride-induced compensated cirrhosis, and the results were compared to those of normal control animals. The rats with cirrhosis exhibited significantly higher plasma renin activity values when compared with the control group. However, plasma concentrations of atrial natriuretic peptide and arginine vasopressin were not significantly different in the two groups. Plasma aldosterone concentrations were significantly higher than those found in the normal control group in approximately 50% of the cirrhotic animals, and were equal to or less than the control values in the rest. This dissociation between plasma renin activity and aldosterone values in some of the cirrhotic animals is interesting and parallels observations made in humans with alcoholic cirrhosis. The results suggest that experimentally induced, apparently compensated cirrhosis may be associated with a perceived decrease in effective circulating volume, and that there is no absolute deficiency of atrial natriuretic peptide in this model of cirrhosis.

Relationship between beta-endorphin/beta-lipotropin, hyperglycemia, and hyperinsulinemia in obese male Zucker rats

The relationship between beta-endorphin(beta-EP)/beta-lipotropin(beta-LP) and insulin secretion in the basal state and after glucose challenge was studied in obese male Zucker rats and their lean littermates. Baseline plasma beta-EP/beta-LP concentrations were similar in the two groups of animals. Baseline plasma insulin and serum glucose concentrations were significantly higher in the obese animals. Following glucose challenge, the increase in plasma beta-EP/beta-LP concentrations was significantly lower in the obese animals than in their lean littermates. Opioid blockade with naloxone failed to alter the baseline hyperinsulinemia and hyperglycemia seen in the obese animals. The data suggest that the hyperinsulinemia in the obese Zucker rat is not due to endogenous hyperendorphinemia as shown in humans with polycystic ovary syndrome. The obese rats showed dissociation between glucose-stimulated plasma levels of beta-EP/beta-LP and insulin levels which may contribute to the hyperinsulinemia and insulin resistance in these animals.

Correlation between macrovascular disease as assessed by bioimpedance plethysmography and various parameters used to assess diabetic "control"

Blood flow in a segment of the leg was determined by bioimpedance plethysmography in 47 diabetic patients and in 19 normal volunteers. The blood flow through the limb, expressed as stroke volume/m2 (SV/m2), was not significantly different in the two populations. SV/m2 showed significant negative correlation with the presence of peripheral vascular disease, fasting serum cholesterol concentration, glycosylated hemoglobin (HbA1c) concentration, and the duration of diabetes. The presence or absence of retinopathy (27.7% of cases) or nephropathy (4.3% of cases) did not show strong association with the SV/m2. Neither the duration of the hypertension nor the systolic or diastolic blood pressure correlated significantly with blood flow in the extremity. These data suggest that only some of the parameters used to assess "control" of diabetic patients can be useful predictors of macrovascular as well as microvascular disease in diabetic patients.

Beta-endorphin/beta-lipotropin release and gonadotropin secretion after acute exercise in physically conditioned males

beta-endorphin (beta-EP) and beta-lipotropin (beta-LPH) concentrations were measured in the basal state and after acute exercise for 15 min or until exhaustion in 6 physically conditioned male volunteers. Serum concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone and prolactin were also measured in the basal state. In addition, the concentrations of the gonadotropins (LH and FSH) were determined after exercise and the gonadotropin response to gonadotropin releasing hormone was assessed before and after exercise. The data show that acute exercise stimulates the release of both beta-EP and beta-LPH which return to base-line levels within 60 min after exercise. This is in contrast to our previously described results in physically unconditioned male volunteers in whom only beta-LPH release was noted after exercise. Serum LH concentrations declined after exercise reaching nadir values between 60 to 150 min after exercise. As we previously reported in physically unconditioned male volunteers, serum FSH concentrations did not change with exercise and the gonadotropin response to LRH stimulation was uninfluenced by exercise. Serum testosterone and prolactin concentration were within the normal range for healthy adult males. We speculate that the difference in beta-EP release with exercise in physically conditioned and unconditioned males represents a difference in processing of the opioid precursor molecule (pro-opiomelanocortin, POMC) in the two groups.