Triglyceride removal efficiency and lipoprotein lipases: effects of Oxandrolone

Effects of continuous combined conjugated estrogen/medroxyprogesterone acetate and 17β-estadiol/norethisterone acetate on lipids and lipoproteins

OBJECTIVES

Various estrogen/progestogen combinations used in hormonal replacement therapy (HRT) have been reported to influence lipid and lipoprotein fractions differently. This motivated a comparative study where the two continuous combined regimens most commonly used in Sweden during the 1990s have been studied regarding effects on lipid profile.

METHODS

In a 1-year prospective, double-blind study, 62 post-menopausal women were randomized to conjugated estrogen (CE), 0.625 mg, and medroxyprogesterone acetate (MPA), 5 mg, or 17beta-estradiol (E2), 2 mg, and norethisterone acetate (NETA), 1 mg. Serum concentrations of lipids and lipoproteins were measured at baseline and after 1 year of treatment.

RESULTS

Both treatment groups significantly lowered the lipoprotein(a) (Lp(a)) levels. The CE/MPA group showed no significant changes in total cholesterol (TC), high-density (HDL) and low-density lipoprotein (LDL), but a significant increase of triglyceride (TG) levels. The E2/NETA group developed a significant lowering of total cholesterol, HDL, and LDL, but no significant changes of TG levels. The magnitude of change in serum concentrations of total cholesterol, HDL and TG differed significantly between the two treatment groups.

CONCLUSIONS

Continuous combined treatment with CE/MPA and E2/NETA equally lowered Lp(a), an important risk factor for cardiovascular disease in women. Apart from this, the two treatments produced different effects on lipids and lipoproteins, findings that are more delicate to interpret.

The choice of hormone replacement therapy or statin therapy in the treatment of hyperlipidemic postmenopausal women

Evidence based treatment of cardiovascular risk factors on outcome in women is still inconclusive given the very large numbers needed to achieve a significant difference in cardiovascular event. Although numerous studies of the effect of hormone replacement therapy (HRT) on risk factors have suggested benefit, the only data from a randomised control trial of HRT in secondary prevention was neutral. Coronary disease-primary prevention: (a) Statins: Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TEX CAPS). The only randomised controlled trial (RCT) to include women. There were fewer coronary heart disease (CHD) events in women but no difference in mortality. (b) HRT: no completed RCT-the results from Womens Health Initiative (WHI) and Women Intervention Study of Long Duration of Oestrogen in the Menopause (WISDOM) are awaited, the former likely to complete in 2004. There are numerous reports of positive observational epidemiological studies for HRT. There is little evidence for statin use in women who will probably not qualify for treatment on global CHD risk assessment, familial hypercholesterolemia and type 2 diabetes excepted. HRT is, therefore, not only appropriate for its multiple effects on lipoproteins, vascular function and insulin sensitivity but also for prevention of osteoporosis. Coronary disease-

SECONDARY PREVENTION

(a) Statins: the major measurable effect of these drugs is to reduce total and LDL cholesterol. In RCT trials, the Scandanavian Simvastatin Survival Study (4S), the Cholesterol and Recurrent Event (CARE) and Long-term Intervention with Pravastatin in Ischaemic Disease (LIPID), approximately 20% of subjects were female, in whom CHD events, but not CHD or total mortality were reduced. (b) HRT: there is data available from a single RCT of continuous combined premarin and medroxyprogesterone acetate (MPA) against placebo, The Heart Estrogen Replacement Study (HERS). A study of 2763 women and mean duration of 4.1 years. This study was neutral, with no reduction in CHD events or mortality. There were more events in the first year, and fewer in years 3-5. Other studies of HRT have been observational and positive for HRT. The effects of treatment on lipoproteins with statins, HRT and combination of statin and HRT have been investigated. In secondary prevention for hyperlipidemic women to achieve cholesterol <5, low density lipoprotein (LDL)<3 mmol/l statins will be first choice, possibly with HRT additionally for its other benefits on cardiovascular risk factors.

Aging-related decline of gonadal function in healthy men: correlation with body composition and lipoproteins

OBJECTIVE

To assess if androgen decline in physiological aging contributes to the concomitant changes in body composition and lipoprotein levels.

DESIGN

Cross-sectional, observational study.

SETTING

A university-based outpatient center.

SUBJECTS

The study comprised 206 healthy volunteers (aged 18-95 years).

MEASUREMENTS

Blood samples were drawn after an overnight fast for the assay of hormones (free testosterone (FT), estradiol (E2), and sex hormone-binding globulin (SHBG)) and lipids (total cholesterol, triglycerides, high-density lipoprotein cholesterol, and lipoprotein Lp(a)). At the same time, body composition was assessed by both anthropometry (fat mass percentage (FM%) estimated from four measures of skinfold thickness using the Durnin and Womersley equation and the Siri equation) and by bioimpedance analysis (FM% estimated using the Segal or Deurenberg equations, respectively, for subjects younger or older than 62 years).

RESULTS

A significant age-related decline was found for FT and E2 concentrations, whereas SHBG levels were related positively with age. No significant association was apparent between hormonal changes and the concomitant modifications of body composition and lipoproteins. Only SHBG showed a significant inverse association between FM% and the waist-to-hip ratio, independent of age. The comparison between older hypogonadal (with FT levels below the lower limit of the normality range assessed in younger subjects) and eugonadal men did not show any significant differences in body composition or lipid profile.

CONCLUSIONS

This study suggests that, in men, androgen decline caused by normal aging does not significantly affect some targets of testosterone action, such as body composition and lipid metabolism. Therefore, androgen supplementation in hypogonadal older men cannot be expected to influence nutritional status and body composition to the same extent that it does other main targets of testosterone action, such as sexual activity and muscle strength. However, we cannot exclude that selected subsets of older patients with low testosterone levels, especially if affected by catabolic disease, could benefit from the effects of androgen administration on nutritional status.

Low-dose progesterone therapy in oestrogenised postmenopausal women: effects on plasma lipids, lipoproteins and liver function parameters

BACKGROUND

Cardiovascular disease among older women is a major health problem and is the leading cause of death in this group in developed countries. The risk is reduced in oestrogen users secondary to favourable lipid changes, but the beneficial effect of oestrogen may be counteracted when concomitant progestogens are administered.

OBJECTIVE

To study the effects of a novel hormone replacement therapy regimen on liver enzymes, lipids and lipoproteins in postmenopausal women.

DESIGN

Prospective open, non-comparative trial for 12 months.

METHODS

40 healthy postmenopausal women, (mean age +/- S.D.), 53.5 +/- 3 years received 0.625 mg of conjugated equine oestrogen daily and 100 mg of micronised oral progesterone (P) for the first 23 days every calendar month for 12 months without interruption.

MAIN OUTCOME MEASURE

Gonadotrophins, liver function parameters and lipoproteins were measured before treatment and at the 6th, 9th and 12th months of treatment.

RESULTS

Compliance with treatment was confirmed by a 33% decrease in mean serum level of follicle stimulating hormone at the end of 1 year of treatment. In the same period, the mean serum cholesterol, LDL and LDL/HDL ratio decreased by 6%, 16% and 23% of the base line levels, respectively. The percentage changes in triglycerides and HDL from the basal levels were +32% (P < 0.001) and +15% (P < 0.05), respectively.

CONCLUSION

These results indicate that near continuous administration of fixed low-dose of P has no adverse effects on the lipid milieu of postmenopausal women when combined with long-term continuous oestrogen replacement therapy provided women with borderline triglyceridaemia are excluded.

Endocrine control of plasma lipoprotein metabolism: effects of gonadal steroids

Gonadal steroids are powerful modulators of plasma lipoprotein metabolism. In general, steroids with oestrogenic activity increase plasma levels of HDL, especially HDL2, and reduce levels of LDL. Steroids with androgenic activity have opposite effects, consistent with the sex difference in HDL and LDL levels. Triglyceride levels are lowered by exogenous administration of androgens and are raised by oral oestrogens, contrary to the observed sex difference in this lipid. The impact of administered gonadal steroids is modified by factors such as dosage and chemical structure, with synthetic steroids having a more pronounced effect than natural hormones. The effects of these steroids may depend on the pre-treatment lipoprotein pattern and endocrine status, and are modified by the route of administration, with oral hormones often having greater metabolic effects than those given parenterally. The net effects of oestrogen and progestagen combined preparations on lipoprotein metabolism depends on the balance between oestrogenic and androgenic activity. In contrast, endogenous changes in sex hormone levels, such as those accompanying puberty, the menstrual cycle and the menopause, have relatively little effect on plasma lipoproteins. Data concerning puberty and castration in males indicate that testosterone is a key factor in the sex difference in HDL levels. There is evidence that loss of ovarian function induces significant increases in LDL level, but endogenous changes in oestrogen levels have little effect on HDL metabolism in women. Changes in triglyceride levels are due mainly to alteration in VLDL secretion and catabolism. LDL levels are controlled by the activity of B100, E receptors and, to a lesser extent, changes in LCAT activity. Gonadal steroids affect HDL levels by altering apoAI synthesis and by controlling the activity of hepatic lipase. Lp(a) levels are increased during early pregnancy but may be decreased by anabolic steroids. The mechanisms behind such actions are unknown. Gonadal hormones influence all areas of plasma lipoprotein metabolism and therefore may affect cardiovascular risk by favourably affecting the plasma lipoprotein profile. In postmenopausal women, use of oestrogens has led to a 60% reduction in cardiovascular disease (Bush et al, 1987). Androgens and progestagens with androgenic properties induce changes in plasma lipoproteins which may increase risk. Further study of the mechanisms involved in these changes is obligatory given the widespread use of these hormones.

Role of plasma lipoproteins in the pathogenesis of atherosclerotic disease, with special reference to sex hormone effects

Plasma lipoproteins constitute a complex lipid transport system. Very low-density lipoproteins transport triglycerides to peripheral tissues, whereas low-density lipoproteins are the main carriers of cholesterol. Cholesterol transport in low-density lipoprotein enters body cells by way of "low-density lipoprotein receptor pathway" but may also be taken up by macrophages by way of the "scavenger pathway." Excessive influx of cholesterol by way of the "scavenger pathway" may result in deposition of cholesterol in arterial walls and atheroma formation. In a yet incompletely known process of "reverse cholesterol transport," cholesterol is carried away from the tissues to the liver by high-density lipoproteins. The above-mentioned transport processes are regulated by a well-synchronized system that involves several enzymes and lipid transport proteins. Under normal conditions, the lipoprotein system is able to balance the flow of cholesterol and other lipids in both directions between the liver and peripheral tissues. This delicate balance may be disturbed by many factors, including contraceptive steroids. The metabolic steps influenced by administration of contraceptive steroids are summarized.

Sex, plasma lipoproteins, and atherosclerosis: prevailing assumptions and outstanding questions

We review the hypothesis that the incidence of coronary heart disease (CHD) is higher in men than in women due to differences in plasma lipoprotein risk factors between the sexes. Men and women appear to be equally susceptible to the effects of lipoprotein risk factors for CHD, and the difference between the sexes in lipoprotein risk factors for CHD appears to be consistent with their being, at least in part, responsible for the sex difference in CHD. This is apparent both when men and women of equal age are compared, and when age-related variations in the sex differences in plasma lipoproteins and CHD are considered. Differences between the sexes in lipoprotein concentrations are still present when sex differences in adiposity, cigarette smoking, physical activity, and diet are taken into account. Evidence relating these sex differences in CHD and lipoproteins to the effects of sex hormones is critically examined. It is commonly accepted that androgens induce changes in lipoprotein concentrations that would predispose towards CHD, whereas estrogens are held to have opposite effects. However, much of the evidence for this comes from studies of changes associated with administration of synthetic gonadal steroids or with changes in gonadal function. Studies of differences in lipoprotein metabolism in normal men and women are extremely limited. In males high-density lipoprotein (HDL) cholesterol levels fall at puberty, correlating with the rise in plasma testosterone concentrations. In females, HDL levels do not change at puberty, despite the rise in estrogen concentrations. Evidence for lipoprotein changes during the menopause, when estrogen levels decline, is equivocal. Similarly, the evidence for an increase in CHD incidence at the menopause is inconclusive. National mortality data indicate that the decreasing sex difference in CHD after 50 years of age is due to a declining rate of increase in men rather than to an acceleration in CHD incidence in women. In men the age-related increase in low-density lipoprotein (LDL) concentrations diminishes beyond 50 years of age, whereas in women the rate of increase remains unchanged. Studies of the effects of gonadectomy are of doubtful relevance in assessing the roles of sex hormones in CHD, and have not been performed with sufficient rigor to provide definitive conclusions.(ABSTRACT TRUNCATED AT 400 WORDS)

Serum lipoproteins, sex hormones and sex hormone binding globulin in middle-aged men of different physical fitness and risk of coronary heart disease

Serum concentrations of lipoproteins, apolipoprotein A-I (Apo A-I), androgens, including biologically active free testosterone (free T), and sex hormone binding globulin (SHBG) and their associations were studied in 3 groups of men of different physical fitness and risk of CHD, consisting of male CHD patients, joggers and healthy controls. Of the 3 study groups, men with angiographically assessed CHD had the lowest HDL-C (P less than 0.002) and highest LDL-C and triglyceride (TG) levels (P = 0.05 and P less than 0.001) and lower 5 alpha-dihydrotestosterone (5 alpha-DHT) levels than joggers (P less than 0.02). Joggers had the highest serum high density lipoprotein cholesterol (HDL-C), Apo A-I and SHBG levels and lowest serum low density lipoprotein cholesterol (LDL-C) compared to the other groups (P less than 0.01). In correlation analysis 5 alpha-DHT was the most significant positive determinant of HDL-C and Apo A-I levels in CHD patients (r = 0.56 and r = 0.55, respectively, P less than 0.05). Moreover, SHBG was significantly positively correlated to both HDL-C and Apo A-I levels in patients, in the whole study group and in healthy men separately (r = 0.37-0.52, P less than 0.01). These significant correlations were also confirmed when age variation and differences in body mass index and smoking were controlled in multivariate analysis and in addition, in multivariate analysis both serum free and total testosterone were inversely related to serum triglyceride (TG) levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Racial (black-white) comparisons of the relationship of levels of endogenous sex hormones to serum lipoproteins during male adolescence: the Bogalusa Heart Study

The cross-sectional relationship of endogenous androgens (testosterone, androstenedione, and dehydroepiandrosterone sulfate [DHEA-S]), estrogen (estradiol) and progestin (progesterone) to serum levels of lipoprotein cholesterol (very low-density [VLDL], low-density [LDL], and high-density lipoprotein [HDL]) and apolipoproteins (apo A-I and apo B) were studied in white (n = 251) and black (n = 258) adolescent boys, ages 11 to 17 years, as part of the Bogalusa Heart Study. Black boys had significantly higher levels of estradiol, HDL cholesterol, and apo A-I, and lower levels of androstenedione and VLDL cholesterol than white boys, independent of age and adiposity. Age was correlated strongly with testosterone and androstenedione, and moderately with DHEA-S and estradiol levels in both races. However, only in white boys was age consistently related to VLDL cholesterol (positively), HDL cholesterol (negatively), and apo A-I (negatively). Overall, testosterone was associated inversely with HDL cholesterol and apo A-I in white boys, while progesterone was related positively to apo A-I in both races after adjusting for age and adiposity. However, these relationships were found to differ with age. Partial correlations between levels of sex hormones and lipoproteins adjusted for age and adiposity showed no associations in the 11 to 12 year age group in boys of either race. A significant positive relation of testosterone to VLDL cholesterol, and inverse relations of testosterone to HDL cholesterol and apo A-I and DHEA-S to HDL cholesterol were apparent only in white boys in the 13 to 14 year age group.(ABSTRACT TRUNCATED AT 250 WORDS)

Chylomicron and very low-density lipoprotein apolipoprotein B metabolism: mechanism of the response to stanozolol in a patient with severe hypertriglyceridemia

Studies of simultaneous autologous 131I-chylomicron (Sf greater than 400) and 125I-very low density lipoprotein (VLDL) (Sf 20 to 400) apolipoprotein B (apo B) were performed both before (triglyceride level c 1500 mg/dL) and during treatment with stanozolol, a 17 alpha-methyl anabolic androgenic steroid (triglyceride level c 750 mg/dL) in a 74-year-old woman with a past history of recurrent chylomicronemic pancreatitis. Both before and during stanozolol treatment chylomicron apo B disappeared rapidly and directly, little appearing in VLDL and virtually none in intermediate (IDL) or low density lipoproteins (LDL). Multicompartmental analysis indicated that the great majority of chylomicron apo B was removed via an extremely rapid compartment (estimated fractional catabolic rate [FCR], 5.0/h), accounting for 66% before and 88% during stanozolol treatment. The remaining 131I-apo B decayed biphasically, with total Sf greater than 400 residence times of 8.6 hours before and 3.7 hours during stanozolol treatment. Hence, despite a moderately depressed adipose tissue lipoprotein lipase activity, the subject's hypertriglyceridemia did not appear to proceed solely from retarded chylomicron removal, nor was the dramatic decrease in triglyceride in response to stanozolol a function only of the acceleration of such removal. VLDL apo B kinetics were analyzed by a multicompartmental model featuring a rapid, stepwise delipidation chain which proceeds either rapidly to IDL and LDL or to a slowly turning over compartment within VLDL. While VLDL. apo B synthesis remained essentially constant, the major effect of stanozolol was a substantial reduction in the fraction of VLDL apo B diverted to this slowly turning over compartment, which decreased from 5.0% before to 1.2% during treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Lipid composition of serum lipoproteins in relation to gonadal hormones during the normal menstrual cycle

Twenty-two normally menstruating women were studied during one menstrual cycle. Blood was collected on 4 occasions and was analysed for free and total cholesterol and triglycerides and phospholipids in the lipoprotein fractions, very-low-density lipoproteins (VLDL), low-density lipoproteins (LDL) and high-density lipoproteins (HDL). Fluctuations in lipid parameters were correlated to serum levels of estradiol-17 beta, progesterone, androstenedione, testosterone and sex-hormone-binding globulin (SHBG). Elevated concentrations of SHBG and HDL-cholesterol and a suppression of LDL-cholesterol were found during the luteal compared to the follicular phase and these findings were interpreted as an estrogenic influence. Consequently the ratio LDL-cholesterol/HDL-cholesterol was depressed during the luteal phase. Triglycerides in serum and VLDL reached a peak at midcycle. When effects on lipid metabolism induced by endogenous steroids were compared to lipoprotein fluctuations exerted by exogenous hormones a parallelism was found in certain variables. However, obvious discrepancies were also found in effects on lipid metabolism, especially for hormones with androgenic properties. The present data underline the necessity of defining in which menstrual phase blood has been collected when lipid metabolism is studied in women of fertile age. Knowledge about metabolic events induced by exogenous sex steroids does not allow conclusions concerning the effects exerted by corresponding endogenous hormones.

Relation between plasma high-density lipoprotein cholesterol and sex hormone concentrations in men

High-density lipoprotein (HDL) cholesterol is inversely associated with risk of heart attack. Sex hormones have been suggested as possible factors contributing to the gender difference of coronary heart disease risk. Little is known about how endogenous sex hormone concentration might be related to HDL cholesterol. The relation was examined in 225 men participating in the Multiple Risk Factor Intervention Trial. Plasma testosterone concentration was positively correlated with HDL cholesterol and the change in testosterone concentration was also positively correlated with change in HDL cholesterol. The relation between testosterone and HDL cholesterol could not be fully explained by age, relative weight, alcohol consumption and cigarette smoking in the cross-sectional study. However, when this relation was examined longitudinally, the partial correlation between changes in testosterone and HDL cholesterol did not quite achieve statistical significance (0.05 less than p less than 0.10). The biologic process that relates HDL cholesterol to testosterone is not known. The results suggest an inverse relation between plasma estradiol concentration and low-density lipoprotein cholesterol, but no statistical significant correlation with HDL cholesterol. In addition, there was no association noted in the current research between estradiol concentrations and the known determinants of HDL cholesterol.

Accumulation of adipocyte cholesterol during hypolipidemic drug treatment in cholesterol-fed rats

An attempt was made to mobilize adipose tissue cholesterol independently of triacylglycerol by feeding cholesterol to intact Fischer 344 rats to 'load' adipocytes followed by hypolipidemic drug treatment in order to lower plasma cholesterol and, hence, adipocyte cholesterol. In this strain of rat, body weight and adipocyte sizes remain relatively constant after 1 year of age. Therefore, alterations in adipocyte cholesterol can be ascribed to factors other than cell size. Both oxandrolone and combined cholestyramine/clofibrate treatment caused significant reductions in plasma cholesterol in cholesterol-fed rats, but cholesterol concentrations in liver were reduced only by cholestyramine/clofibrate treatment. Oxandrolone enhanced the development of liver fatty liver in the cholesterol-fed rats, but cholestyramine/clofibrate significantly reduced liver triacylglycerol concentrations. Adipocyte cholesterol in the epididymal depot was significantly elevated, not lowered, in both concentrations. Adipocyte cholesterol in the epididymal depot was significantly elevated, not lowered, in both groups of drug-treated animals. Subcutaneous adipocytes from rats receiving drug treatment also contained more cholesterol, especially in rats given oxandrolone. Increments in adipocyte cholesterol were associated with decreases in the absolute amounts of apolipoproteins, A-I and A-IV, as measured by densitometric scanning of electrophoretic gels. Under the present experimental conditions, changes in plasma cholesterol scanning of electrophoretic gels. Under the present experimental conditions, changes in plasma cholesterol concentration did not adequately reflect the cholesterol content of either liver or adipose tissue.

Reduction in high density lipoproteins by anabolic steroid (stanozolol) therapy for postmenopausal osteoporosis

The effects of stanozolol, 17-methyl-2H-5 alpha-androst-2-eno [3,2-c] pyrazol-17 beta-ol, on lipoprotein levels were assessed in a short-term (6 wk) prospective study of 10 normolipidemic, postmenopausal, osteoporotic women. While total cholesterol and triglyceride levels remained constant, equal and offsetting responses were seen in low density lipoprotein (LDL) cholesterol (+30.9 +/- 28.1 mg/dl [mean +/- S.D.], p less than 0.01, a 21% increase) and high density lipoprotein (HDL) cholesterol (-32.5 +/- 11.9 mg/dl [mean +/- S.D.], p less than 0.001, a 53% decline). Hence the LDL/HDL ratio increased dramatically, from 2.5 +/- 0.7 to 6.8 +/- 2.5. Within HDL, stanozolol was associated with a greater decline in HDL2 (from 26.0 +/- 7.4 mg/dl to 3.8 +/- 1.9 mg/dl, p less than 0.001, an 85% decrease) than HDL3 (which diminished from 35.7 +/- 3.2 to 24.1 +/- 5.8 mg/dl. p less than 0.001, a 35% decrease). The major HLD apolipoproteins also declined (A-I by a mean of 41% and A-II by 24%, both p less than 0.001). Postheparin hepatic triglyceride lipase increased (off treatment 74 +/- 42 nmole free fatty acid min-1 mole-1, on treatment 242 +/- 110, n = 6, p = 0.06). All changes were reversed by 5 wk following termination of the drug. These lipoprotein changes suggest caution in the long term prescription of stanozolol, particularly in those without overriding clinical indications for its use.

Lipid and carbohydrate metabolism studies in oophorectomized women: effects produced by the addition of norethisterone acetate to two estrogen preparations

Norethisterone acetate (NET) was administered to 11 oophorectomized women, primed with either 17-C-alkylated ethinylestradiol (EE) or the non-alkylated estrogen, estradiol valerate (E2V), to evaluate the effects on lipid metabolism. Blood samples were drawn after a period without hormonal replacement therapy and after 6 weeks on each estrogen and estrogen-progestogen combination. Serum and lipoprotein lipids were followed and an oral glucose tolerance test was performed with blood glucose and plasma insulin determinations. NET reversed the increase in serum triglycerides induced by EE and, when added to either estrogen, increased low density lipoproteins and reversed the high density lipoprotein lipid increase induced by both estrogens. The NET + EE, but not the NET + E2V combination, imparied glucose tolerance.

Lipid metabolic studies in oophorectomised women: effects on serum lipids and lipoproteins of three synthetic progestogens

Norethisterone acetate, medroxyprogesterone acetate and levonorgestrel were administered to oophorectomised women to evaluate the effects they have on lipid metabolism. Blood samples were drawn after a 3 wk period without hormone therapy and after 3 wk on each progestogen. Serum and lipoprotein lipids were followed and an oral glucose tolerance test with blood glucose and plasma insulin determinations were performed. The nortestosterone derivatives, norethisterone acetate and levonorgestrel, decreased high density lipoprotein cholesterol as well as alpha-lipoproteincholesterol, while the 17-hydroxyprogesterone derivative medroxyprogesterone acetate did not. Norethisterone acetate and medroxyprogesterone acetate impaired glucose tolerance. A difference between nortestosterone derivatives and 17-hydroxyprogesterone derivatives having an effect on high density lipoproteins is suggested.

Administration of dehydroepiandrosterone enanthate to oophorectomized women--effects on sex hormones and lipid metabolism

Eight bilaterally oophorectomized women were given a depot injection of 200 mg DHEA-enanthate to study the effect on endocrine and lipid metabolism. A decrease in sex-hormone binding globulin (SHBG) and an increase in androstenedione was found 14 and 30 days after the injection. No changes could be detected in LH, FSH, oestrone, oestradiol or oestriol. Testosterone showed a tendency towards an increase. As compared to pre-treatment values, plasma lipids were unaltered after 30 days. A decrease in high density lipoproteins (HDL), cholesterol and in very low density lipoproteins (VLDL), free cholesterol, total cholesterol and phospholipids were seen in the lipid composition of the lipoproteins on day 30. These findings are in agreement with previous data reported after the administration of drugs with androgen-like effects. The relative fatty acid composition of plasma lecithin revealed only minor changes while the fatty acid composition of cholesterol esters indicated a decreased portion of essential fatty acids. These results suggest, in agreement with previous studies, an impaired endogenous cholesterol formation in the liver. The results from the analysis of the fatty acid composition of lecithin and cholesterol esters might indicate a decreased percentage of exogenous (dietary) cholesterol ester in plasma.

Pancreatitis, familial hypertriglyceridemia, and pregnancy

Interrelationships between pregnancy, hypertriglyceridemia, and pancreatitis were assessed in three women with familial hypertriglyceridemia. One subject had known familial hypertriglyceridemia, familial type V hyperlipoproteinemia, prior to conception. In this woman a progressive increase in triglyceride levels to more than 3,000 mg/dl during the first two trimesters required dietary intervention and hospitalization at 28 weeks' gestation. Use of an isocaloric National Institutes of Health type V diet reduced triglyceride levels to less than 900 mg/dl; the pregnancy was uneventful with term delivery of a healthy neonate. The familial hypertriglyceridemia was covert in the other two women until term. In one subject, subsequently shown to have familial type V, acute hemorrhagic pancreatitis with a pancreatic pseudocyst, shock, and hypocalcemia developed at 39 weeks' gestation; the neonate was safely delivered, and the mother survived. In the second, entirely asymptomatic subject, triglyceride levels greater than 5,000 mg/dl were discovered incidentally at term cesarean section during delivery of a healthy neonate. With a fat restricted diet, plasma triglyceride levels abruptly fell post partum to less than 500 mg/dl, and subsequent studies revealed familial type III hyperlipoproteinemia. Routine quantitation of plasma cholesterol and triglyceride levels or simple visual examination of fasting plasma for triglyceride-induced opacity or "milky" appearance should be done during early pregnancy. This would allow the obstetrician to identify women with severe familial hypertriglyceridemia prior to the superimposition of the physiologic hyperlipidemia of pregnancy upon familial hypertriglyceridemia with resultant, and often catastrophic, acute pancreatitis.

High density lipoproteins during hypolipidemic therapy. A comparative study of four drugs

The high density lipoprotein HDL) response of 14 hyperlipidemic subjects to four hypolipidemic agents was studied through serial measurement of HDL cholesterol and apolipoproteins A-I and A-II before and during 3 months each (separated by 2 months off drug) of clofibrate (2 g/day, n = 14), colestipol (20 g/day, n = 12), para-amino salicylic acid--ascorbate (PAS-C, 6--8 g/day, n = 14) taken in random sequence and oxandrolone (7.5 mg/day, n = 11) as the final drug. The maximal effect of each drug appeared by the first monthly evaluation, and A-1, A-II and HDL cholesterol levels returned to pretreatment levels by one month after discontinuation of each agent. With clofibrate, HDL cholesterol increased by 16 +/- 20% from baseline (mean +/- SD) (P less than 0.05), A-I by 11 +/- 13% (P less than 0.05) and A-II by 39 +/- 17% (P less than 0.01). During oxandrolone HDL cholesterol declined by 36 +/- 20% from baseline (P less than 0.01), A-I by 21 +/- 13% (P less than 0.01), and A-II by 16 +/- 11% (P less than 0.025). Neither PAS-C nor colestipol exerted major effects on HDL, or any of the variables although both were associated with a slight rise in the A-I/A-II ratio (11 +/- 15% and 12 +/- 12%, respectively).

A long-term study of the efficacy of oxandrolone in hyperlipoproteinemias

Oxandrolone, an anabolic steroid, significantly reduced serum triglycerides in type III, IV, and V hyperlipoproteinemia, with a concomitant decrease in pre-beta lipoproteins. Its slightly enhancing effect on serum cholesterol and absolute increase in beta lipoproteins might eventually discourage its administration in type II patients. Alpha lipoproteins always remained at low levels. In addition to its hypotriglyceridemic action,, oxandrolone induced a slight reduction in uric acid and alkaline phosphatases. Untoward side effects were not observed even after prolonger therapy. Therefore, oxandrolone might deserve a place among the few available triglyceride-reducing therapies.

Effect of contraceptive steroids on arginine-stimulated glucagon and insulin secretion in women. III. Medroxyprogesterone acetate

The effect of medroxyprogesterone acetate (MPA) on basal circulating lipids, arginine-stimulated glucagon and insulin secretion, and glucose tolerance was studied in normal women. After 5 days of oral MPA treatment (10 mg/day), there was a small but significant decline in basal circulating triglycerides. No changes were observed in fasting plasma concentrations of cholesterol, free fatty acids, glucagon, insulin, or glucose; in the plasma glucagon, insulin, or glucose responses during L-arginine infusion; or in the plasma insulin or glucose responses during oral glucose tolerance tests. There was no correlation of any of these parameters with the observed decline in fasting plasma triglyceride concentrations. These results confirm previous reports of no consistent changes in lipid or glucose homeostasis in women using derivatives of 17alpha-acetoxyprogesterone derivatives for contraceptive purposes, and suggest that MPA may be a suitable alternative for those women who develop hyperlipemia or glucose intolerance when they use contraceptive agents which contain derivatives of ethinyl estradiol and nortestosterone.

Effect of progestins on glucose and lipid metabolism

Gestamimetic amounts of progesterone enhance basal and glucose-stimulated insulin production. Contraceptive doses of synthetic progestins cause a moderate increase or no change in glucose-stimulated insulin production, depending on route of administration and species tested. Estrogens potentiate the insulinotropic effects of progesterone and the synthetic progestins. Basal serum triglyceride concentrations are generally unaffected by progesterone or 17 alpha-acetoxyprogesterone treatment but may decrease during 19-nortestosterone administration. Glucose tolerance does not change during treatment with gestamimetic doses of progesterone alone but may improve in rats and monkeys during concurrent estrogen administration. By contrast, deterioration of glucose tolerance is observed in women treated concurrently with synthetic estrogen plus 19-nortestosterone derivatives and, occasionally, with 19-nortestosterone derivatives alone. No consistent changes in glucose metabolism have been observed after treatment with 17 alpha-acetoxyprogesterone derivatives alone. The cause of the species-related differences in glucose metabolism during 19-nortestosterone treatment is obscure.

Effect of sex hormones on protamine inactivated and resistant postheparin plasma lipases

Effects of estrogens and the synthetic anabolic-androgenic steroid, Oxandrolone, on extrahepatic (protamine inactivated) and hepatic (protamine resistant) lipases in postheparin plasma, were assessed in 15 subjects with familial hypertriglyceridemia. In six women receiving conjugated equine estrogen (1.25 mg/day), mean (+/- SE) postheparin protemine inactivated triglyceride lipase (PI-TGL) was depressed to 0.23 +/- 0.10 mumol FFA/ml/hr, and protamine resistant lipase was depressed to 5.3 +/- 0.5 mumol FFA/ml/hr. In the 2-wk period after estrogens were discontinued, PI-TGL remained depressed, 0.54 +/- 0.24, while PR-TGL increased to 7.3 +/- 0.88, p=less than 0.05. Mean triglycerides fell insignificantly from 628 +/- 136 to 447 +/- 44 mg/100 ml when estrogens were discontinued. There was no significant correlation between changes in PR-TGL and triglycerides when estrogens were stopped. In four women with familial hypertriglyceridemia, Oxandrolone significantly increased PR-TGL in two, increased PI-TGL in three, and reduced triglycerides in two. In five men with familial hypertriglyceridemia, Oxandrolone reduced triglycerides in four, increased PR-TGL in four, but had no effect on PI-TGL. For the nine hypertriglyceridemic subjects increments in PR-TGL failed to correlate significantly with decrements in triglyceride, (r=0.309, p is greater than 0.1). Selective alteration of PR-TGL and PI-TGL by estrogens and Oxandrolone may provide an approach to better understanding of the interaction of lipases and triglycerides in familial and acquired hypertriglyceridemia.

Familial and acquired type V hyperlipoproteinemia

The nature of Type V hyperlipoproteinemia including mode of presentation, prominent clinical and biochemical features, and genetics, was examined in 29 adults presenting with the Type V lipoprotein phenotype. Initially 23 of the 29 patients had various metabolic stimuli (diabetes out of control, estrogenic agents, pancreatitis, ethanolism) superposed on their acute hypertriglyceridemia. After metabolic stabilization, 17 of the 29 subjects were shown to have familial hypertriglyceridemia. In the 17 kindreds with familial hypertriglyceridemia, the lack of a specific, distinctive genetic marker for the Type V genotype and for the Type IV genotype restricts the conclusion that the pattern of inheritance was consistent with an autosomal dominant trait.

Effect of contraceptive steroids on arginine- stimulated glucagon and insulin secretion in women. II. Carbohydrate and lipid physiology in insulin-dependent diabetics

The effect of contraceptive steroids on aminogenic glucagon secretion was studied in six insulin-dependent diabetic women. After 2 wk treatment with combined mestranol (80 mug) plus norethindrone (1 mg) daily, the mean peak plasma glucagon response to arginine infusion was suppressed to one-fourth of control levels. This was associated with a small but significant decrease in mean basal plasma cholesterol concentrations. There were no changes in basal plasma triglyceride, free fatty acid, glucose, insulin, or alpha-amino nitrogen concentrations or in daily insulin requirements during mestranol plus norethindrone treatment. These results confirm previous reports of no consistent changes in the insulin requirements of insulin-dependent diabetic women using contraceptive steroids and suggest that these women may not experience dramatic changes in their lipid metabolism during contraceptive therapy.

Effect of contraceptive steroids on arginine-stimulated glucagon and insulin secretion in women: I-Lipid physiology

To evaluate the effect of contraceptive steroids on endogenous glucagon and insulin secretion, theta-arginine was infused intravenously in normal young women before and during selective steroid treatment. The effect of the combination of an estrogen derivative (mestranol), plus norethindrone (Norinyl, Syntex) was compared to the effect of ethinyl estradiol alone and to norethindrone alone. All three steroid schedules resulted in suppression of aminogenic insulin secretion. However, glucagon secretion was reduced only with ethinyl estradiol alone or the combination of mestranol plus norethindrone. In accordance with previous reports, treatment with an ethinyl estradiol derivative alone or in combination with norethindrone resulted in a tendency for elevated serum lipid concentration, while norethindrone alone resulted in a significant reduction in serum lipid concentration. These observations suggest an inverse relationship between aminogenic glucagon secretion and serum lipid concentration as influenced by contraceptive steroids. It is suggested that the metabolic effects of these steroids may be mediated in part by the associated alterations in pancreatic hormone secretory capacity.

Effect of oxandrolone treatment on the activity of lipoprotein lipase, hepatic lipase and phospholipase A1 of human postheparin plasma

The effect of a synthetic steroid, oxandrolone, on total postheparin plasma lipolytic activity, postherpain hepatic lipase activity, lipoprotein lipase and phospholipase A1 was studied in seven patients with hypertriglyceridemia. The mean total postheparin lipolytic activity increased 100 per cent during oxandrolone tratement (p smaller than 0.05). This change was caused mainly by postheparin hepatic lipase, whose activity increased on the average more than 2.5 times (p smaller than 0.001). The change in postheparin plasma-lipoprotein-lipase activity was insignificant. A highly significant correlation (r equals +0.87, p smaller than 0.01) was observed between the activities of postheparin hepatic lipase and phospholipase A1 before and during oxandrolone treatment. No relation was observed between serum triglyceride level and various postheparin lipase activities, or between the changes induced by oxandrolone in the level of serum lipids and the activities of postheparin lipases. We conclude that oxandrolone increases the activities of postheparin plasma hepatic lipase and phospholipase A1 but has little influence on lipoprotein lipase.

Effects of estrogenic compounds on triglyceride kinetics

Paired studies of triglyceride kinetics were made in 8 women on and off postmenopausal estrogen supplementation. When estrogens were discontinued, mean very-low-density lipoprotein triglyceride (VLD-TG) and VLD-TG turnover rate fell respectively from 555 to 349 mg/100 ml, and from 30-18 mg/kg/hr (p smaller than 0.01). Maximal turnover rate (Vmax) and VLD-TG concentration at 1/2 V max (Km), were 82.4 mg/kg/hr and 704.14 mg/100 ml on estrogen and fell to 41.83 and 347.51 when estrogen was discontinued (p smaller than 0.01). Estrogen supplementation did not lengthen VLD-TG half-life or diminish the fractional turnover rate of VLD-TG. Estrogens apparently increase VLD-TG by augmenting VLD-TG production rates.

Selective measurement of two lipase activities in postheparin plasma from normal subjects and patients with hyperlipoproteinemia

An assay has been developed for specific measurement of two different lipase activities in postheparin plasma. Lipoprotein lipase, derived from extrahepatic sources, is measured as protamine-inactivated lipase activity; hepatic lipase activity is protamine-resistant under the conditions of this assay. In 100 normal subjects, both enzyme activities were noted to be related to age and sex. Protamine-resistant lipase, which comprised 46-95% of the total activity, was highest in men over 18. Protamine-inactivated lipase activity was greatest in younger males and was age-correlated in women, doubling between the second and sixth decades. In 12 patients with hyperchylomicronemia, including five previously shown to have familial type I hyperlipoproteinemia, protamine-inactivated lipase activity was markedly reduced, whereas protamine-resistant lipase was below normal in only 1. The results were not due to lack of plasma activator, presence of plasma inhibitor, or diet, and the deficiency was not overcome by increasing the provoking dose of heparin from 10 U to 75 U/kg. Mean values for both lipase activities were not reduced in 32 other patients with hyperchylomicronemia, nine with "floating beta" lipoproteins (type III hyperlipoproteinemia), and 23 with hyperprebetalipoproteinemia (type IV). Mean protamine-resistant lipase activity was below normal in a group of four women with hypothyroidism, in whom protamine-inactivated lipase was not reduced. Both of the lipase activities were capable of hydrolyzing lipid in very low-density lipoproteins, but the relative rate of hydrolysis of chylomicrons by protamine-resistant lipase was markedly limited. These results indicate the importance of distinguishing between lipases of hepatic and extra-hepatic origin in the measurement of postheparin lipolytic activity.