Effects of a progestogen and a sequential type oral contraceptive on plasma vitamin A, vitamin E, cholesterol and triglycerides

Progesterone regulation of implantation-related genes: new insights into the role of oestrogen

Genomic profiling was performed on explants of late proliferative phase human endometrium after 24-h treatment with progesterone (P) or oestradiol and progesterone (17β-E₂+P) and on explants of menstrual phase endometrium treated with 17β-E₂+P. Gene expression was validated with real-time PCR in the samples used for the arrays, in endometrium collected from early and mid-secretory phase endometrium, and in additional experiments performed on new samples collected in the menstrual and late proliferative phase. The results show that late proliferative phase human endometrium is more responsive to progestins than menstrual phase endometrium, that the expression of several genes associated with embryo implantation (i.e. thrombomodulin, monoamine oxidase A, SPARC-like 1) can be induced by P in vitro, and that genes that are fully dependent on the continuous presence of 17β-E₂ during P exposure can be distinguished from those that are P-dependent to a lesser extent. Therefore, 17β-E₂ selectively primes implantation-related genes for the effects of P.

Effects of menstrual cycle and oral contraceptive use on serum levels of lipid-soluble antioxidants

OBJECTIVE

The purpose of this study was to examine the influence of menstrual cycle and oral contraceptive use on serum levels of lipid-soluble antioxidants.

STUDY DESIGN

In this cross-section study, nonfasting blood samples were collected twice from 10 healthy premenopausal women during the follicular phase (between days 8 and 11) and the luteal phase (between days 18 and 22) of their same menstrual cycle. In addition, blood samples from 15 premenopausal women who used oral contraceptive for at least 6 months and 40 women who did not use oral contraceptive were collected randomly at any day of the menstrual cycle. Serum levels of coenzyme Q10, alpha-tocopherol, gamma-tocopherol, beta-carotene, alpha-carotene, and lycopene were determined using high pressure liquid chromatography.

RESULTS

Serum coenzyme Q10 and alpha-tocopherol levels were significantly lower during the follicular phase compared with the luteal phase of the same menstrual cycle (P < .05). Oral contraceptive use also significantly decreased coenzyme Q10 and alpha-tocopherol (P < .001). Other antioxidant levels were comparable.

CONCLUSION

Alterations in coenzyme Q10 and alpha-tocopherol levels during the menstrual cycle and in oral contraceptive users should be taken into consideration, concerning the future antioxidant research in premenopausal women. Further studies are needed to investigate the potential role of endogenous and exogenous ovarian hormones on oxidative stress in women.

Plasma reduced and total ascorbic acid in healthy women: effects of smoking and oral contraception

This is the first report of both reduced (RAA) and total (TAA) plasma ascorbic acid levels in women who smoke and are on oral contraception. 155 normal healthy subjects were investigated. A study questionnaire was completed including age, method of contraception, smoking status, and food intake at breakfast, prior to attending the clinic. Biochemical assays were promptly carried out without knowledge of subject's clinical or dietary status. One-way analysis of variance revealed that oral contraception per se, barrier or IUD methods have no effect on plasma ascorbic acid levels. The mean values (mg/dl +/- SD) for plasma RAA between smokers and nonsmokers were 0.512 +/- 0.241 and 0.601 +/- 0.263; and that for TAA were 0.565 +/- 0.232 and 0.682 +/- 0.231, respectively. Significant decreases in both plasma RAA (p less than 0.05) and TAA levels (p less than 0.001) were observed in smokers. Age was an interacting variable. No association of smoking or oral contraceptive use was seen with RAA or TAA levels among women less than 26 years, but decreases in both RAA and TAA levels were evident among smokers aged 26 years or older. The present study emphasizes the total exposure to smoking, e.g., pack years, is a significant confounding variable in the study of plasma ascorbic acid levels.

Cancer of the cervix uteri and vitamin A

The concentrations of retinol and beta carotene were measured in serum samples taken from 113 women with cervical cancer, 32 with invasive and 81 with pre-invasive disease, and compared with those from 226 age-matched control women. There was little difference in serum retinol levels between women with cancer of the cervix, at any stage, and the control women, after adjusting for potential confounding factors. Serum beta carotene concentrations were likewise similar in women with invasive disease and the controls. However mean beta carotene levels were significantly reduced in women with pre-invasive disease compared to the controls (221.3 cf. 291.6 micrograms l-1, P less than 0.05). This reduction was more evident amongst women with a diagnosis of carcinoma-in-situ (mean 213.1 micrograms l-1 than amongst those with severe dysplasia (mean 228.7 micrograms l-1. There is a negative trend between beta carotene and risk of pre-invasive disease which is of borderline significance. These data have also been used to investigate the effects of smoking and oral contraceptive usage on the serum levels of retinol and beta carotene. Both habits tend to increase retinol and decrease beta carotene concentrations.

Changes in plasma vitamin A in lactating and non-lactating oral contraceptive users

Plasma vitamin A and retinol-binding protein (RBP) concentrations have been studied in women using oral contraceptives (OC) for up to 4 years. In eight women taking an oestrogenic OC(1 mg of norethisterone acetate + 50 micrograms of ethinyloestradiol) values almost doubled within 6 months, but diminished somewhat after 4 years. Saturation of RBP with retinol remained fairly constant. Five lactating women who took progestogen-only OC (30 micrograms of levonorgestrel or 350 micrograms of norethisterone) showed no significant alteration in plasma vitamin A or RBP concentrations as compared with nine lactating non-OC users. All lactating women showed significant differences between the highest and lowest plasma vitamin A (P less than 0.005) and RBP (P less than 0.05) concentrations during the first 6 months of lactation. Highest values occurred 11-12 weeks postpartum and the lowest at 15-17 weeks. Percentage saturation of RBP with retinol was significantly higher (P less than 0.005) when vitamin A concentration was highest.

Hormonal regulation of retinoic acid-binding proteins in the mammary gland

A cytosolic retinoic acid-binding (RAB) protein that sediments specifically as a 2S component on sucrose density gradients was detected in the mammary glands of virgin, pregnant and lactating rats. Mammary cytosol from pregnant rats contained significantly higher concentrations of cytosolic RAB protein than did cytosol from either virgin or lactating rats. The glands of pregnant animals exhibited increased concentration of cytosolic RAB protein during the first 5 days of pregnancy, and a steady decline was observed thereafter. The concentration of cytosolic RAB protein dropped to the value observed during lactation on the day 20 of pregnancy. Moreover, throughout lactation, low concentrations of cytosolic RAB protein were maintained. Daily treatment of virgin and lactating animals with 5 micrograms of oestradiol-17 beta for 1 week increased cytosolic RAB protein to concentrations comparable with those seen in pregnant rats. Progesterone, however, did not affect the mammary cytosolic RAB protein content of virgin rats. These results suggest hormonal involvement in the regulation of cytosolic RAB protein concentration of mammary gland during differentiation.

Serum 25-hydroxycholecalciferol levels in women using oral contraceptives

A study has been made of the serum 25-hydroxycholecalciferol (25-HCC) levels in six groups of women. Significant differences were found between the one pregnant group and the two reference groups as well as between the one pregnant group and two of the three groups using oral contraceptives. No significant differences were found between the reference groups and the ones taking oral contraceptives with oestrogenic concentrations of 0.05 mg or 0.03 mg ethinyl oestradiol for more than one year. It can therefore be concluded that in contrast with most other vitamins, the serum 25-HCC levels are not influenced by the use of oral contraceptives with different oestrogenic concentrations, even over a long period of time.