Ovarian insulin-like growth factors.
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Female↗
Biomedical subjects
L Poretsky
Publications and source records attributed to L Poretsky.
Hyperinsulinemia and human chorionic gonadotropin synergistically promote the growth of ovarian follicular cysts in rats.
Tonically elevated serum luteinizing hormone (LH) and hyperinsulinemia are prominent features of polycystic ovary syndrome (PCO) in women, but the relative roles of LH and insulin in the pathogenesis of PCO is still unknown. The present study was undertaken to determine the effect(s) hyperinsulinemia might have on the induction of follicular cysts by LH/human chorionic gonadotropin (hCG) in the rat. Beginning on day 85 of age, adult female rats were given one of the following in vivo treatments: (1) vehicle alone; (2) a high-fat diet to control for the effects of weight-gain; (3) up to 6 U insulin per day; (4) 50 micrograms gonadotropin-releasing hormone (GnRH) antagonist (GnRHant) per day; (5) 1.5 IU hCG twice daily; (6) insulin + hCG; (7) insulin + GnRHant; (8) hCG + GnRHant; or (9) hCG + insulin + GnRHant. After 22 days of treatment, animals were killed on day 23, trunk blood was collected, and ovaries were excised for histological study. Regular cycles, assessed by vaginal smears, ceased after 10 days for most animals in treatment groups receiving hCG, but continued in all other treatment groups. All the animals in each hCG-treated group developed either unilateral or bilateral cystic ovaries, while no animals in the groups not receiving hCG developed follicular cysts. More animals from each group treated with both hCG and insulin possessed bilateral ovarian cysts than did rats treated with hCG alone: 80% and 60%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
On the paradox of insulin-induced hyperandrogenism in insulin-resistant states.
I have reviewed recent studies that shed light on the paradox of insulin-induced ovarian hyperandrogenism in insulin-resistant states. Depending on the circumstances of the particular syndrome, insulin could act on the ovaries of insulin-resistant patients by activating IGF-I receptors, insulin receptors, hybrid insulin/IGF-I receptors, or any combination of these receptors. Further studies will uncover precise mechanisms of insulin-induced ovarian hyperstimulation in specific syndromes of insulin resistance.
Androgens↗
Pneumocystis carinii infection of the thyroid in a hypothyroid patient with AIDS: diagnosis by fine needle aspiration biopsy.
A 49-yr-old homosexual man with acquired immunodeficiency syndrome presented with a left-sided neck mass. He was found to have a firm goiter. He was clinically euthyroid, but had laboratory evidence of primary hypothyroidism. Radioactive iodine scan of the thyroid showed homogeneous uptake over an enlarged right lobe and absence of uptake over the left lobe. Two fine needle aspiration biopsies of the thyroid revealed the presence of Pneumocystis carinii (P. carinii) organisms on the Gomori's methenamine silver strain. After courses of iv and oral therapy with trimethoprim-sulfamethoxazole, a third fine needle aspiration biopsy failed to reveal any organisms. A repeated radioactive iodine scan of the thyroid showed return of uptake over the left lobe. Thyroid function tests normalized with levothyroxine, and the goiter decreased in size. To our knowledge, this is the first report of hypothyroidism associated with P. carinii infection of the thyroid. P. carinii infection should be considered in the differential diagnosis of human immunodeficiency virus infected individuals presenting with cold thyroid nodules. Fine needle aspiration biopsy is a valuable tool in assessing these patients.
Acquired Immunodeficiency Syndrome↗
Regulation of human ovarian insulin receptors in vivo.
Insulin participates in regulating ovarian function in normal and in pathological states. This effect of insulin may be mediated by ovarian insulin receptors. We have previously characterized human ovarian insulin receptors and began to examine their regulation in vitro. The present study examines regulation of human ovarian insulin receptors in vivo. Stromal ovarian tissue was obtained from 21 women during an indicated surgical procedure. Ten women were premenopausal and 11 were postmenopausal. Specific 125I-insulin binding to stromal ovarian fragments ranged from 2.5% to 7.3%/mg protein. 125I-insulin binding to stromal fragments correlated positively with 125I-insulin binding to circulating leucocytes (r = .57; P less than .01). When postmenopausal and premenopausal women were analyzed separately, this relationship persisted in postmenopausal women (r = .70; P less than .05), but not premenopausal women. 125I-insulin binding to stromal ovarian fragments correlated negatively with age (r = -.63; P = .005). 125I-insulin binding to stromal ovarian fragments tended to correlate negatively with plasma insulin levels in postmenopausal women (r = -.67; P = .06), but not in premenopausal women. Plasma insulin levels correlated negatively with serum SHBG (r = -.62; P = .003). The percent free testosterone levels correlated positively with plasma insulin levels in premenopausal women (r = .95; P = .0001), but not in postmenopausal women.(ABSTRACT TRUNCATED AT 250 WORDS)
Age Factors↗
Subnormal follicular-phase serum progesterone levels and elevated follicular-phase serum estradiol levels in young women with insulin-dependent diabetes.
In a search for possible hormonal reasons for the loss of protection from myocardial infarction seen in diabetic women, serum levels of estradiol, progesterone, and luteinizing hormone were compared throughout a menstrual cycle (17 points) in eight healthy nonsmoking women and five otherwise healthy nonsmoking insulin-dependent diabetic women. The total length of the menstrual cycle and the lengths of the follicular and luteal phases did not differ between the groups. During the periovulatory and luteal phases, there was no significant intergroup difference with respect to any of the three hormones. During the follicular phase, in both groups, there was a plateau in serum progesterone concentration, with the level approximately 42% lower in the diabetic group (12.0 +/- 6.6 ng/dl versus 20.7 +/- 5.7; P less than 0.0001). Follicular-phase serum estradiol showed a rising curve in both groups; day-by-day comparison (days -10 to -3 before the luteinizing hormone peak) showed consistently higher levels in the diabetic group (mean, 108 pg/ml versus 95 pg/ml; P less than 0.001). The follicular-phase serum estradiol to progesterone ratio was nearly twice as high in the diabetic group as in the normal group (8.9 versus 4.6), a difference that was highly significant. The finding of elevated serum estradiol and subnormal serum progesterone concentrations during the follicular phase is so far unique to women with insulin-dependent diabetes mellitus. The possibility that this pronounced abnormality in diabetic women may be related to coronary disease merits testing in suitable in vivo and in vitro models of atherogenesis.
Adult↗
Type I insulin-like growth factor receptors in human ovarian stroma.
Hyperandrogenism observed in a variety of hyperinsulinemic states is thought to be due to an effect of insulin mediated through the type I insulin-like growth factor (IGF) receptors. These receptors, however, have not yet been demonstrated in normal human ovarian cells capable of androgen production. We now report the presence of type I IGF receptors in membrane preparations of human ovarian stroma. The ovarian stromal tissue was obtained from women undergoing indicated oophorectomy. Stromal plasma membranes were prepared. Specific 125I-IGF-I binding was 6.6 +/- 0.2%/100 micrograms protein. The affinity constant estimated by Scatchard analysis was 4.6 X 10(-9) M. 50% inhibition of 125I-IGF-1 binding was observed at 5 ng/ml of IGF-1. Specificity of the 125I-IGF-I-binding sites was confirmed by analogue specificity studies and in experiments utilizing monoclonal antibody to the IGF-I receptor, alpha-IR-3. IGF-II and insulin competed with 125I-IGF-I for the binding sites, but with an affinity significantly lower than that of IGF-I: 50% inhibition was observed at approximately 60 ng/ml of IGF-II or insulin. alpha-IR-3, a monoclonal antibody with high specificity for the type I IGF receptor, effectively inhibited 125I-IGF-I binding in a dose-dependent manner, confirming that the 125I-IGF-I binding was indeed to the type I IGF receptor. We conclude that type I IGF receptors are present in human ovarian stroma. These receptors may mediate effects of insulin on the ovary in hyperinsulinemic insulin-resistant states.
Binding, Competitive↗
Endocrinologic and metabolic manifestations of the acquired immunodeficiency syndrome.
The endocrine abnormalities associated with acquired immunodeficiency syndrome (AIDS) are reviewed. These include adrenal insufficiency, hyporeninemic hypoaldosteronism, panhypopituitarism, hypogonadism, and alterations in thyroid function tests. AIDS-related infections or neoplasms may lead to hypercalcemia, whereas malabsorption may cause hypocalcemia. The possibility that AIDS-associated cachexia and hypertriglyceridemia may be caused by cachectin (tumor necrosis factor) is discussed, along with possible therapy for cachexia with megestrol acetate. Ketoconazole, sulfonamides, and pentamidine have specific, potentially deleterious metabolic effects when used in AIDS patients. Because treatment of endocrinological abnormalities of AIDS is often effective, improved diagnosis and appropriate therapy of these abnormalities will result in improved quality of life and, possibly, longer survival of patients with AIDS.
Acquired Immunodeficiency Syndrome↗
Absence of antibody to human immunodeficiency virus in long-term, socially rehabilitated methadone maintenance patients.
Human immunodeficiency virus (HIV) infection has become widespread among parenteral drug abusers. We measured antibody to HIV and hepatitis B virus markers in 58 long-term, socially rehabilitated methadone-maintained former heroin addicts. None of the 58 had antibody to HIV, but one or more markers of hepatitis B virus infection were seen in 53 (91%). The duration of methadone maintenance was 16.9 +/- 0.5 years, and the median dose of methadone was 60 mg (range, 5 to 100 mg). Before methadone treatment, the patients had abused heroin parenterally for 10.3 +/- 1.7 years, and they had engaged in additional high-risk practices for HIV infection. We conclude that successful outcomes during methadone maintenance treatment are associated with sparing of parenteral drug abusers from HIV infection.
Female↗
Specificity spillover at the hormone receptor.
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Hormones↗
Hormonally active long-term culture of human ovarian cells: initial characterization.
At present, to our knowledge, there are no long-term hormonally active cultures of normal human stromal ovarian cells. This report describes a method of developing such a system. Normal human stromal ovarian cells from three patients were cultured in McCoy's 5A tissue culture medium at 37 degrees C, 5% CO2, 95% humidity. The cells rapidly acquired fibroblastic appearance and grew in monolayers. The cells were trypsinized and passaged weekly. Tissue culture medium was collected and assayed for progesterone. The cells were initially producing 33.2 +/- 2.64 ng/mg protein of progesterone. By the eighth to twelfth passage, however, progesterone was no longer detectable in the medium. When the cells of the 12th passage were incubated with cholesterol, progesterone production resumed (8.9 +/- 0.09 ng/mg protein). When pregnenolone was used as a substrate, progesterone production was also present (8.06 +/- 0.24 ng/mg protein). Moreover, in the cells incubated with pregnenolone, progesterone production could be stimulated by adding 50 ng/mL FSH, or 50 ng/mL insulin to the incubation medium. Progesterone content of the medium increased to 11.3 +/- 0.29 ng/mg protein and 10.97 +/- 0.54 ng/mg protein respectively (P less than .05). The cells were also able to convert androstenedione to estrone. When the cells were incubated with 3 mumol/L androstenedione, estrone content of the medium ranged from 318 +/- 13 to 382 +/- 14 pg/mg protein. This finding suggests that aromatase is present in cultured human ovarian cells. These cells have now been maintained for 12 passages. A hormonally active long-term culture of normal human ovarian cells could be a useful tool in studies of ovarian physiology.
Adult↗
Persistent insulin resistance after normalization of androgen levels in a woman with congenital adrenal hyperplasia. A case report.
Treatment of a woman who had 21-hydroxylase deficiency and insulin resistance resulted in normalization of her high androgen levels. The insulin resistance persisted, indicating that the hyperandrogenism was not contributing to it.
Adrenal Hyperplasia, Congenital↗
Methadone and thyroid-function tests.
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Humans↗
The effects of experimental hyperinsulinemia on steroid secretion, ovarian [125I]insulin binding, and ovarian [125I]insulin-like growth-factor I binding in the rat.
We randomized 32 cycling female Sprague-Dawley rats (82 days old) into experimental and control groups (16 animals/group). Hyperinsulinemia was induced and maintained for 22 days in the experimental group with NPH human insulin (Novolin, Squibb-Novo, Princeton, NJ) as previously described. Controls received an identical volume of vehicle. Fifteen minutes before death, each rat received a sc injection of 100 ng synthetic GnRH (Factrel, Ayerst Laboratories, New York, NY). The mean serum insulin level was significantly higher in the insulin-treated group than in the control group (165 +/- 57 vs. 49 +/- 9 microU/ml; P less than 0.05). The mean final weight also was significantly higher in the insulin-treated group (283 +/- 4 vs. 242 +/- 7 g; P less than 0.001). There were no significant differences in mean final serum levels of testosterone, estradiol, estrone, or androstenedione or in GnRH-stimulated serum levels of LH or FSH. The androstenedione to estrone ratio, however, was significantly lower in the insulin-treated group (2.5 +/- 0.3 vs. 3.4 +/- 0.2; P less than 0.01), suggesting that aromatase activity increased with hyperinsulinemia. Specific [125I]insulin binding to ovarian tissue homogenates was lower in the insulin-treated group (1.7 +/- 0.1% vs. 2.6 +/- 0.6%/0.2 mg protein; P greater than 0.05), suggesting that ovarian insulin receptors tended to down-regulate with hyperinsulinemia. Specific [125I]insulin-like growth factor I [( 125I]IGF-I) binding to ovarian tissue homogenates, in contrast, was significantly higher in the insulin-treated group (13.3 +/- 1.4% vs. 7.2 +/- 0.6%/0.2 mg protein; P less than 0.05), suggesting that ovarian IGF receptors up-regulated with hyperinsulinemia. The affinity of neither [125I]insulin binding nor that of [125I]IGF-I binding changed significantly, with the 50% inhibition point remaining between 2.0 and 5.0 ng/ml for each peptide in both groups. We conclude that hyperinsulinemia increases ovarian [125I]IGF-I binding and stimulates aromatase activity in the rat. These phenomena, if also true in women, could be important factors contributing to the ovarian hyperstimulation observed in various hyperinsulinemic states.
Animals↗
Regulation of insulin receptors in the human ovary: in vitro studies.
The association between insulin resistance and ovarian hyperstimulation has led to a hypothesis that insulin stimulates ovarian steroidogenesis. This possible effect of insulin on the ovary could be mediated by either the insulin receptor or the type I insulin-like growth factor (IGF) receptor, both of which have been described in the human ovary. We examined the in vitro regulation of insulin receptors by LH, FSH, multiplication-stimulating activity (MSA), and insulin in ovarian stromal fragments from 24 women. [125I]Insulin binding was measured in the presence and absence of increasing concentrations of insulin, IGF-I, LH, and FSH. Neither LH nor FSH competed with [125I]insulin for binding sites, but preincubation with LH or FSH reduced [125I]insulin binding by 19-38%. Preincubation with MSA reduced [125I]insulin binding by 34-48%. The affinity of the insulin receptors, determined by Scatchard analysis, did not change (Ka = 3.3 X 10(8) mol-1). A concentration of 10 ng/mL insulin in the preincubation medium reduced [125I]insulin binding by 40%, whereas an insulin concentration of 50 or 500 ng/mL completely obliterated specific [125I]insulin binding. [125I]Insulin binding fully recovered, however, 4 h after termination of tissue exposure to insulin. The specificity of [125I] insulin binding was confirmed by studies with IGF-I. We conclude that of the hormones examined, insulin is the most potent regulator of human ovarian insulin receptors in vitro. Down-regulation of insulin receptors by insulin was reversed within 4 h after withdrawal of insulin. MSA, FSH, and LH also down-regulated the number of human ovarian insulin receptors in vitro, but were less potent. These phenomena, if also present in vivo, could be important factors in the regulation of ovarian function by insulin in normal and pathological states.
Adult↗
Recovery of beta-cell function postpartum in a patient with insulin-dependent diabetes mellitus.
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Adolescent↗
Hyporeninemic hypoaldosteronism associated with acquired immune deficiency syndrome.
Four patients with the acquired immune deficiency syndrome (AIDS) and persistent unexplained hyperkalemia were studied. Testing with cosyntropin (0.25 mg intravenously) revealed normal baseline and stimulated cortisol levels and adequate aldosterone stimulation. The baseline aldosterone level was low for the degree of hyperkalemia. Renin/aldosterone stimulation testing was performed by intravenous injection of 80 mg of furosemide followed by four hours of upright posture. This study showed low baseline renin and aldosterone levels and inadequate renin and aldosterone stimulation. Three patients were subsequently treated with fludrocortisone (0.1 to 0.2 mg per day), with normalization of serum potassium levels. It is concluded that hyporeninemic hypoaldosteronism is responsible for hyperkalemia in some patients with AIDS and that treatment with fludrocortisone is effective in these cases.
Acidosis↗
The gonadotropic function of insulin.
We have reviewed the role of insulin in ovarian physiology. Clinical observations and experimental data strongly support the hypothesis that insulin possesses gonadotropic activity, when acting alone or with FSH or LH. This idea is further supported by the recent discovery of insulin in follicular fluid. The idea that insulin has gonadotropic function can explain a variety of clinical observations, which otherwise are difficult to understand. For example, manifestations of ovarian hypofunction (primary amenorrhea, late menarche, anovulation, low pregnancy rate, and early menopause) in IDDM can be understood if it is accepted that insulin is necessary for the ovary to reach its full steroidogenic potential. The idea that insulin affects ovarian steroidogenesis also helps to understand the observation that hyperandrogenism frequently accompanies each of the various insulin-resistant states, regardless of the latter's etiology (e.g. genetic deficiency in the number of insulin receptors, antiinsulin receptor antibodies, obesity, etc.). The explanation for this association is based on the idea that hyperinsulinemia intensifies ovarian steroidogenesis, which manifests clinically as hyperandrogenism. Continuous stimulation of the ovary by insulin over a long period of time possibly produces morphological ovarian changes, such as hyperthecosis or polycystic changes; these changes commonly are observed among women with insulin resistance. The effects of insulin on ovarian cells are mediated possibly through binding of the peptide to its own receptor or to the IGF-1 receptor (the specificity spillover phenomenon). The latter could be an important mechanism in cases of insulin resistance. Potential mechanisms underlying the gonadotropic activity of insulin include direct effects on steroidogenic enzymes, modulation of FSH or LH receptor number, synergism with FSH or LH, or nonspecific enhancement of cell viability. The gonadotropic function of insulin adds yet another note to what has been termed a symphony of insulin action. Further investigation into this new area may yield greater insights not only into normal ovarian physiology, but also into the pathogeneses of such diverse entities as PCO, obesity, diabetes mellitus, and the syndromes of insulin resistance and acanthosis nigricans.
Animals↗