Contraceptive steroid treatment affects steroid binding proteins and the percentage of free 17 beta-estradiol and testosterone in the cynomolgus monkey (Macaca fascicularis)

The levels of steroid binding globulins were characterized in cynomolgus monkeys that were treated with contraceptive steroid preparations delivered either by intravaginal rings (CVR) or orally (OC) in the diet. Levonorgestrel (dNG) was the bioactive progestin and the estrogen was either 17 beta-estradiol (E2) in the CVR treatment or ethinyl estradiol (EE) in the OC treatment. Both contraceptive treatments lowered sex hormone binding globulin (SHBG) levels below those observed in males (P less than 0.05) and normal females (P less than 0.01). Corticosteroid binding globulin (CBG) was elevated (P less than 0.01) in the OC treatment, demonstrating the potency of EE. The distribution of E2 and testosterone (T) between binding to SHBG or albumin and the unbound fraction was calculated after the determination of the percentage of free steroid by centrifugal ultrafiltration. Both contraceptive treatments increased the percentage of free T and E2 (P less than 0.01) in the subset of monkeys that were evaluated, but the percentage bound to SHBG and albumin were different only for the CVR group (P less than 0.05). Decreased total T concentrations in the treatment groups offset any increase in free T concentrations associated with an increase in the percentage of free T. The differences in the distribution of binding to SHBG associated with these contraceptive steroid treatments was influenced more by the reduction in the binding capacity of SHBG than by the displacement of E2 and T from SHBG by dNG.     

Regulation of plasma corticosteroid-binding globulin in adult cynomolgus monkey (Macaca fascicularis) during different reproductive states

The plasma concentration of the corticosteroid-binding globulin (mCBG) has been measured in Macaca fascicularis, during different stages of reproduction and under hormonal treatments. The mCBG level was determined by a specific electroimmunoassay. There was no difference between females in the follicular phase and intact males; mCBG concentrations were respectively (mean +/- SEM) 469 +/- 53 and 443 +/- 25.6 nmol/l. The mCBG levels levels were similar during both the luteal (469 +/- 33.5 nmol/l) and the follicular phase (469 +/- 53 nmol/l). Compared to intact males, the mCBG levels were higher (P less than 0.05) in castrated males (527 +/- 6.6 nmol/l). During gestation, no systematic variations were found and the mCBG levels were not statistically different from the values found during the follicular phase. When estradiol benzoate was administered to castrated animals, the mCBG concentrations increased rapidly. In contrast, the values were reduced slightly by testosterone treatment. The sex-steroid action on the mCBG levels was discussed and compared with the mSBP levels. We question also, the mechanisms involved in the regulation of the mCBG levels during pregnancy.     

Serum hormone levels in pregnant cynomolgus monkeys

Serum levels of estradiol (E2), progesterone (P), prolactin (Prl), monkey chorionic gonadotropin (mCG), dehydroepiandrosterone sulfate (DHEAS), and cortisol (C) in pregnant cynomolgus monkeys are described. mCG, E2, and Prl patterns resembled those of pregnant rhesus monkeys. P patterns differed from data from the literature. DHEAS patterns did not follow E2 patterns. C levels did not change during pregnancy.     

17beta-estradiol regulation of melanin-concentrating hormone and neuropeptide-E-I contents in cynomolgus monkeys: a preliminary study.

Melanin-concentrating hormone (MCH) and neuropeptide-E-I (NEI) regulate several behaviors and neuroendocrine functions in rats. Possible influence of these peptides on sexual behavior and reproduction in mammals other than rodents prompted us to investigate: 1) The sites of synthesis of MCH and NEI in the brain of a non-human primate (M. fascicularis); 2) The effect of 17 beta-estradiol (E2) benzoate (E2B) on pro-MCH-derived peptide concentrations in the hypothalamus of the ovariectomized (OVX) cynomolgus monkeys (M. fascicularis). Expression of MCH mRNA and peptides was examined by Northern blotting, RT-PCR and RP-HPLC/RIA. Our results demonstrate that the MCH gene is predominantly expressed in hypothalamus of macaque. E2B exposure of OVX monkeys provoked parallel phasic variations in the MCH-immunoreactivity (IR) and NEI-IR. NEI-IR and to a lesser extent MCH-IR, showed a transient increase (associated with the estradiol peak) at 30 h with a final rise of both MCH-IR and NEI-IR observed at the time (72 h post E2B) of the luteinizing hormone (LH) surge. RP-HPLC analysis of peptide extracts revealed the presence, in addition to mature MCH and NEI, of different MCH-IR and NEI-IR forms in the hypothalami of control and E2B-treated monkeys. Taken together, our results indicated that hypothalamic MCH and NEI contents are regulated after E2B treatment and they suggest the possible involvement of these peptides in the regulation of the pre-ovulatory midcycle LH surge in primates.     

Regulation of plasma sex-steroid-binding protein in adult cynomolgus monkeys (Macaca fascicularis) during different reproductive states

Levels of the sex-steroid binding protein (mSBP) have been characterized in Cynomolgus monkeys, during different stages of reproduction and under hormonal treatments, by an immunoassay allowing a specific and accurate measurement of the protein itself. Using an antiserum specific for native human SBP, we have determined the mSBP level by electroimmunodiffusion. This method correlates closely with the binding capacity measured by a steady-state polyacrylamide electrophoresis. The levels are lower in males (M = 88 +/- 8.6 nmoles/1, n = 6) than in females in the follicular phase (M = 123 +/- 4.4 nmoles/1, n = 5, p less than 0.001) and in castrated males (M = 172 +/- 13.3 nmoles/1, n = 3, p less than 0.001). During gestation, the SBP level decreases (M = 69 +/- 16.3 nmoles/1, n = 7, in the latter part of pregnancy), but during lactation, it is similar to follicular values. Estrogen treatment fails to increase SBP levels in castrated animals, but the values are reduced by testosterone treatment. Since these results are different from those observed in women, we question the validity of using monkeys as models for understanding the mechanisms controlling the concentration of SBP in human blood.     

Effect of testosterone and 17beta-estradiol treatment on sex steroid binding proteins in the male of the green frog Rana esculenta

In this paper we report the effect of gonadectomy and/or long-term sex steroid (testosterone and estradiol-17beta) treatment and prolonged captivity (two months) on testosterone and estradiol-17beta binding proteins (TBP and EBP, respectively) in the plasma of the male of the green frog Rana esculenta. Experiments were carried out during different periods of the reproductive cycle. Gonadectomy and prolonged captivity were carried out in winter, when the spermatogenic activity slowed down and the concentration of circulating androgens was high. Both gonadectomy and prolonged captivity resulted in a significant decrease in TBP binding activity, which could not be restored by the hormonal treatment. On the contrary, when the hormonal treatment was carried out in the early summer, when the spermatogenesis was active but the concentration of circulating androgens was low, a significant increase in TBP binding activity was observed. Neither gonadectomy, nor the prolonged captivity, nor the hormonal treatment affected EBP levels. Our data indicate that TBP apparent changes in response to testosterone and estradiol-17beta treatment varied according to the period of the reproductive cycle, an indication that studies on sex steroid binding proteins regulation should take into consideration the internal endocrine condition before drawing any final conclusion especially in species with a seasonal mode of reproduction.     

Association between testosterone, estradiol and sex hormone binding globulin levels in men with type 1 diabetes with nephropathy

Male sex is a risk factor for development and progression of diabetic nephropathy; however, the relationship between sex hormone levels and diabetic nephropathy in type 1 diabetic men is unknown. This was a prospective follow-up study as part of the nationwide Finnish Diabetic Nephropathy (FinnDiane) Study; 297 patients were followed for 5.9 ± 1.5 years. Serum total testosterone (Tt) and estradiol (Te), calculated free testosterone (cFt) and estradiol (cFe) and sex hormone binding globulin were measured at baseline and correlated with urinary albumin excretion rate, estimated glomerular filtration rate and markers of metabolic syndrome. Diabetes without renal disease was associated with decreased Tt (p < 0.001), Te (p < 0.001) and cFt (p = 0.001) levels compared with healthy non-diabetic men. With progression of renal disease from micro- to macroalbuminuria, this decrease in serum Tt was even more pronounced. Cox regression showed that cFt and cFe were independent predictors of the progression from macroalbuminuria to end-stage renal disease. Our study shows that men with type 1 diabetes exhibit dysregulated sex hormone levels, which is most pronounced in men with progressive renal disease, suggesting that sex hormones may play a role in the pathogenesis of diabetic nephropathy associated with type 1 diabetes.     

Pituitary prolactin and growth hormone levels during different reproductive states in mice with a high or a low lactational performance

The pituitary prolactin and growth hormone (GH) levels were determined by disc electrophoresis on 10% polyacrylamide gel during the virginal and pregnant stages and on Day 12 of lactation, using C3H/He and C57BL/6 mice. The former had been shown to be superior to the latter in both mammary development and lactational performance. The pituitary prolactin levels were significantly higher in C3H/He mice than in C57BL/6 mice during the virginal and pregnant stages. However, no strain differences existed in the prolactin levels on Day 12 of lactation. Little difference in the prolactin levels was found between estrus and diestrus, and the levels declined gradually with the advance of pregnancy in both strains. The levels decreased after 1 hr of suckling preceded by 8-hr removal of young on Day 12 of lactation in both strains, but the difference between before and after suckling was statistically significant only in C3H/He mice. Both pituitary GH content and concentration were significantly higher in C3H/He mice than in C57BL/6 mice during the virginal stage and the content was also higher in C3H/He mice during the pregnant stage. However, there existed no strain difference in the levels on Day 12 of lactation. Little change in the pituitary GH levels was observed during the different reproductive states in both strains.     

Direct effect of plasma sex hormone binding globulin (SHBG) on the metabolic clearance rate of 17 beta-estradiol in the primate

Sex hormone binding globulin (SHBG) has been shown to be a major determinant of testosterone clearance in the primate. It has also been suggested that SHBG would also be a determinant of estradiol clearance (MCR-E2). However, published studies have suggested that the MCR-E2 do not always vary with changes in the level of SHBG. Therefore, the present study was undertaken to address this issue. The baseline MCR-E2 was determined in adult male pigtail macaques (Macaca nemestrina). Following the baseline determination of MCR-E2 the animals were infused with either purified human (h) SHBG or antibody against hSHBG, which also has a high degree of cross-reactivity with primate SHBG. Following the infusions of either hSHBG or anti-SHBG, MCR-E2 was again determined. In addition, luteinizing hormone (LH) was measured using a mouse Leydig cell bioassay. Following the infusion of hSHBG, a marked increase in serum SHBG was noted and the MCR-E2 decreased. Associated with the increase in SHBG, the SHBG bound T levels decreased and LH increased. Following the infusion of antibody, serum SHBG decreased, and the MCR-E2 also decreased. With the decrease in SHBG following the antibody infusion, non-SHBG bound T increased and serum LH fell. This study demonstrates that an increase in the serum SHBG levels is associated with a decrease in MCR-E2, however, an acute decrease in serum SHBG also decreases the MCR-E2. This later result demonstrates that factors in addition to serum SHBG binding may be important in determining the MCR-E2.     

Serum luteinizing hormone levels in cattle under various reproductive states

Serum lutinizing hormone (LH) levels in cattle during various reproductive states were measured by radioimmunoassay. A sharp LH peak observed at estrus (22.72 ± 5.68 ng/ml) was about 26 times higher than at other stages of the cycle (0.87 ± 0.06 ng/ml). LH levels during the first 90 days of pregnancy (0.75 ± 0.15 ng/ml) were similar to those of the estrous cycle, except during estrus, while those during the second (0.22 ± 0.07 ng/ml) and third trimesters of pregnancy (0.22 ± 0.08 ng/ml) were significantly lower. Higher levels than those of the cycling cows, except during estrus, were seen in ovariectomized cows (2.21 ± 0.56 ng/ml). Levels of LH in cows with cystic follicles (2.00 ± 0.49 ng/ml) were higher than the levels in the cycle. LH levels in bulls (1.29 ± 0.39 ng/ml) were comparable to that of estrous cows. Serum LH of calves increased with age from 1.00 ± 0.32 ng/ml (less than 30 days of age), to 2.30 ± 0.83 ng/ml (181 to 210 days of age), and the level after 151 days was significantly higher than that of the cyclic cows, except during estrus.     

Sex hormone-binding globulin and thyroxine-binding globulin levels in premature thelarche

Premature thelarche is defined as the isolated development of breast tissue in girls less than 8 years of age. Although breast development is an estrogen-dependent process, these girls do not have elevated serum estrogen levels, and the hormonal basis for their condition is unclear. We studied the levels of two estrogen-dependent transport proteins, sex hormone-binding globulin (SHBG) and thyroxine-binding globulin (TBG), in order to determine if there was evidence for a more subtle estrogen effect in girls with premature thelarche. SHBG levels in girls with premature thelarche were not significantly different from those of prepubertal girls of the same ages and were significantly lower than those in girls undergoing pubertal development at the appropriate age (P less than 0.05) and in normal women (P less than 0.001). There was no statistically significant difference in TBG levels between the girls with premature thelarche and prepubertal controls. There was also no significant difference in TBG levels between prepubertal girls and girls in early puberty. In contrast, women had TBG levels that were significantly lower than those in all girls studied. We conclude that the estrogen exposure (whether endogenous or exogenous) of girls with premature thelarche is less than that of girls in early true puberty and similar to that of other prepubertal girls. Further, changes in serum TBG are not as sensitive an indicator of estrogen effect as is breast development or changes in SHBG. This study also suggests that large amounts of exogenous estrogens are not an element in the development of premature thelarche.     

Associations of testosterone and sex hormone binding globulin with adipose tissue hormones in midlife women

Objective:

Regulators of adipose tissue hormones remain incompletely understood, but may include sex hormones. As adipose tissue hormones have been shown to contribute to numerous metabolic and cardiovascular disorders, understanding their regulation in midlife women is of clinical importance. Therefore, we assessed the associations between testosterone (T) and sex hormone binding globulin (SHBG) with leptin, high molecular weight (HMW) adiponectin, and the soluble form of the leptin receptor (sOB‐R) in healthy midlife women.

Design and Methods:

Cross‐sectional analyses were performed using data from 1,881 midlife women (average age 52.6 (±2.7) years) attending the sixth Annual follow‐up visit of the multiethnic Study of Women's Health Across the Nation.

Results:

T was weakly negatively associated with both HMW adiponectin and sOB‐R (r = ?0.12 and r = ?0.10, respectively; P < 0.001 for both), and positively associated with leptin (r = 0.17; P < 0.001). SHBG was more strongly and positively associated with both HMW adiponectin and sOB‐R (r = 0.29 and r = 0.24, respectively; P < 0.001 for both), and more strongly and negatively associated with leptin (r = ?0.27; P < 0.001). Adjustment for fat mass, insulin resistance, or waist circumference only partially diminished associations with HMW adiponectin and sOB‐R, but attenuated associations with leptin. In conclusion, in these midlife women, lower SHBG values, and to a lesser extent, higher T levels, were associated with lower, or less favorable, levels of adiponectin and sOB‐R, independent of fat mass.

Conclusions:

These data suggest that variation in these adipose hormones resulting from lower SHBG levels, and possibly, though less likely, greater androgenicity, may contribute to susceptibility for metabolic and cardiovascular outcomes during midlife in women.

     

The steroid hormone levels and receptors of steroid hormone receptors in rat muscles during physical exertion

It is shown that the testosterone content in skeletal muscles of female albino rats is 2-fold decreased, while the estradiol content-1.5-fold increased and progesteron content showed no changes after systematic physical exercises. The pharmacokinetic investigations showed that androgen half-life in the organism decreased from 8 to 5 h under physical exercises. The amount of androgen receptors in cytosol of skeletal muscles increases from 1.34 +/- 0.08 to 1.71 +/- 0.10 fmol/mg per 1 mg of protein. Kd is 0.40 +/- 0.03 and 0.48 +/- 0.08 nM, respectively. Sensitivity of the organism to hormonal signal play an important role in the metabolism regulation in skeletal muscles along with the hormonal content change during the organism adaptation to physical exercises.     

Acceleration of adenovirus replication and increased virion production by treatment with the steroid hormone 17 beta-estradiol.

We report here that concentration of an estrogen known to promote enhanced transformation and to increase oncogenicity of rat embryo cells, accelerate the production and increase the yield of progeny virions in adenovirus type 12 (Ad 12)-infected HEp-2 cells. Further, measurement of the incorporation of radioactive RNA and DNA precursors indicated that macromolecular synthesis in the estrogen-treated, infected cells was accelerated. Possible explanations for this observation are discussed.     

Sex hormone binding globulin expression and colocalization with estrogen receptor in the human Fallopian tube.

The detection of sex hormone binding globulin (SHBG) or SHBG mRNA in several sex steroid target tissues, has raised the possibility that SHBG modulates the action of sex steroids outside the vascular compartment. The presence of SHBG mRNA was investigated by RT-PCR in the poly (A+) RNA fraction of the human Fallopian tube. Human and rat liver were used as positive and negative control tissues, respectively. The electrophoretic analysis of the amplified PCR products showed bands at 219 bp, corresponding to the expected size of the SHBG cDNA, in the Fallopian tube and human liver but not in rat liver, indicating that SHBG might be synthesized by the Fallopian tube. The cellular localization of SHBG and of estrogen receptor (ER) was examined by immunohistochemistry in consecutive sections of Fallopian tube tissues for individual staining or double immunostaining in the same section. Specific immunostaining of SHBG was present in the epithelial, vascular and muscle cells of the ampullary and isthmic region. In epithelial cells, immunoreactive SHBG was present in the apical end with the highest concentration close to the luminal membrane. The ER was localized in the nuclei of epithelial, stromal and muscle cells of the ampulla and isthmus. Double immunostaining showed that SHBG and ER are colocalized principally in epithelial cells of the ampulla and in muscle cells of the isthmus. In conclusion, the detection of SHBG and SHBG mRNA and the localization of SHBG in estrogen target cells was shown. These findings support the hypothesis that SHBG might regulate sex steroid action at the tissue level.     

Effects of dexamethasone on the levels of plasma corticosteroid binding globulin in rats and monkeys.

Rat marrow cells were preincubated for 45 hours with 5.5 × 10^?4M sodium hexachloroiridate. This treatment abolished DNA synthesis whilst improving cell survival over that of controls. The synthesis of RNA, protein and glycoprotein continued and could be further increased by the addition of erythropoietin for up to 44 more hours. Heme synthesis also continued in the absence of DNA synthesis but could not be stimulated by erythropoietin.