Library of Excerpts

Menapause and Menstuation

[abstract]The clinical association between glucose intolerance, hyperinsulinaemia, insulin resistance and hyperandrogenism is well recognized in premenopausal women with polycystic ovarian disease. We examined the hypothesis that fasting plasma glucose levels might be related to endogenous androgen levels in postmenopausal women in the absence of overt clinical disease. 2. In a Southern Californian cohort of 848 nondiabetic postmenopausal women aged 50-79 years, fasting plasma glucose levels positively correlated with levels of the endogenous androgens dehydroepiandrosterone sulphate and free testosterone and negatively with sex-hormone-binding globulin across the whole range of glucose and hormone levels. Mean dihydroepiandrosterone sulphate and free testosterone levels were 16% and 46% higher, respectively, and mean sex-hormone-binding globulin levels 27% lower in the top compared with the bottom quartile of fasting plasma glucose levels. This relationship was independent of age, body mass index, cigarette smoking habit and exogenous oestrogen use. 3. These findings raise questions about the possible physiological role of androgens in the regulation of glucose metabolism and insulin resistance and, possibly, in the mediation of the some of the cardiovascular consequences of diabetes in women. (Khaw KT, Barrett-Connor E (1991) Fasting plasma glucose levels and endogenous androgens in non-diabetic postmenopausal women. Clin Sci (Colch) 80(3):199-203)

"It is known that women who smoke have an earlier menopause than those who do not. (Whitley et al., 1981; Buchman et. al., 1978)" (MacMahon, B., Trichopoulos, D., Cole, P. & Brown, J. (1982) Cigarette smoking and urinary estrogens. New England Journal of Medicine 307: pp. 1062)

"As compared with nonsmokers and exsmokers, smokers had substantially and significantly lower levels of all three major estrogens in the luteal phase of the menstrual cycle. ... In follicular specimens estrogen concentrations for smokers did not differ significantly from those of nonsmokers. However, in the luteal specimens current smokers had levels about one third below those of nonsmokers or exsmokers for all three estrogens. The differences were significant for each estrogen and for the total." (MacMahon, B., Trichopoulos, D., Cole, P. & Brown, J. (1982) Cigarette smoking and urinary estrogens. New England Journal of Medicine 307: pp. 1063)

"Small suggests that oestrus periods of a week or longer in female primates seem excessive if females are fertile for only 24 hours, and she notes that the human ovum is fertilizable for (an estimated mean of) about 24 hous." (James, W.H. (1989) On female primate sexual behavior. Current Anthropology 30,1: pp. 77)

“Plasma gonadotropin levels throughout the regular menstrual cycle in 10 Japanese women were measured daily using radioimmunoassay. At the peak of ovulation, mean FSH levels were 17.6 +/- 7.9 mlU/ml and mean LH levels were 75.2 +/- 26.0 mlU/ml. At midcycle, the mean gonadotropin levels were significantly lower in Japanese women than in Nigerian womenwho, as reported by Nylander (1973), had a high frequency of twinning. It is, therefore, suggested that the low frequency of dizygotic twinning in Japanese women might be related to their low output of gonadotropin. “ (Soma H, Takayama M, Kiyokawa T, Akaeda T, Tokoro K (1975) Serum gonadotropin levels in Japanese women. Obstet Gynecol 46 (3): 311)

"By comparing adolescent girls' testosterone results derived from saliva sampled during the follicular phase (Day 1 to 15) with testosterone results obtained from saliva sampled during the luteal phase (from Day 16 to the onset on menstuation) of the menstrual cycle, we found no significant differences between the phases at Stage 4 when girls' mean age was 14.43. At Stage 5, when girls were 15.40 years old on average, significant differences emerged in testosterone means of the day.... Testosterone means were higher in the luteal than in the follicular phase of the menstrual cycle." (Hassler & Birbaumer, 1988) at each stage of the study." (Hassler, M & Nieschlag, E. (1991) Salivary testosterone and creative musical behavior in adolescent males and females. Developmental Neuropsychology 7: 516)

"The ethnographic record {e.g., A French Army Surgeon (1898/1972), a 30-year specialist in genitourinary diseases} makes reference to numerous anatomical distinctions which show a similar pattern of whites being between blacks and Orientals. These include the placement of female genitals (Orientals front and high; blacks back and low); angle and texture of erection (Orientals parallel to body and stiff, blacks at right angles to body and flexible); salient buttocks, breasts, and muscularity (Orientals least, blacks most); and size of genitalia (Orientals smallest, blacks largest). We averaged the ethnographic data on erect penis and found the means to approximate: Orientals, 4 to 5.5 in. in length and 1.25 in. in diameter; Caucasions, 5.5 to 6 in. in length and 1.5 in. in diameter; blacks, 6.25 to 8 in. in length and 2 in. in diameter. Women were proportionate to men, with Orientals having smaller vaginas and blacks larger ones, relative to Caucasians. Clitoral size differed in length: in European women, 1.2 in.; in African women, 2 in. variations were noted; in French West Indies, the size of the penis and vagina covaried with amount of black admixture; Arab men, who were often mixed with black, had larger penises than Europeans. Recent data show similar patterns. Measurements taken from living subjects as well as those at autopsy, show the size of testes is twofold lower in Asian men than Europeans (9 g vs 21 g), a difference too large to be accounted for entirely in terms of body size (Diamond, 1986; Short, 1984). Concomitantly, as mentioned, Asian women have lower ovulation rates than Caucasian women, as indexed by dizotic twin frequency, with the frequency per 1000 across several Asian populations being < 4, while for Caucasians it is 8, and for blacks 16 per 1000 (Bulmer, 1970; Diamond, 1986). Contrary to the general trend, Freeman (1934) observed that, at autopsy, American blacks had less heavy testes than American whites (13g vs 15g). Freeman (1934), however, did find that black women had heavier ovaries than white women. Subsequently Daniel, Fienstein, Howard-Peebles, and Baxley (1982) found no black-white difference in testicular volume among American adolescents, while Ajmani, Jain, and Saxena (1985) found larger scrotal circumference in Nigerians than Europeans (212.6 mm vs 195.1 mm or 8.37 in. vs 7.68 in.). A French Army Surgeon (1988/1972) also provided early observations that, in speed of sexual maturation, Orientals < whites< blacks. Several subsequent studies are confirmatory. In the United States, blacks are more precoscious than whites as indexed by age at menarche, first sexual experience, and first pregnancy (Malina, 1979). A national probability sample of American youth found that by age 12, 19% of black girls had reached the highest stages of breast and pubic hair development, compared to 5% of white girls (Harlan, Harlan, & Grillo, 1980), although the same survey found white and black boys to be similar (Harlan, Grillo, Coroni-Huntley, & Leaverton, 1979). Subsequently, Westney, Jenkins, Butts, and Williams (1984) found that 60% of 11-year-old black boys had reached the stage of acelerated penis growth in contrast to the white norm of 50% of 12 1/2-year-olds. This genital stage significantly predicted onset of sexual interest, with 2.2% of the black boys experiencing intercourse by age 11. While some surveys found that Oriental girls enter puberty as early as whites (Eveleth & Tanner, 1976), others suggest that in both physical development and onset of interest in sex, the Japanese, on the average, lag 1.5 to 2 years behind white Americans (Asayama, 1975). (Rushton, J.P. & Bogaert, A.F. (1987) Race differences in sexual behavior: Testing an evolutionary hypothesis. Journal Research in Personality 21(4): pp. 536-7)

"Although this is a preliminary study, the evidence for synchrony and suppression of the menstrual cycle is quite strong, indicating that in humans there is some interpersonal physiological process which affects the menstrual cycle." (McClintock, M.K. (1971) Menstrual synchrony and suppression. Nature 229: pp. 245)

[citations removed] "In general the two experiments express the well-known left hemisphere superiority for verbal processing and right hemisphere superiority for face perception. However, while the right field advantage for lexical decisions did not change throughout the menstrual cycle, the significant left field advantage for face perception in the menstrual phase disappeared during the mentrual cycle and even shifted in the prementrual phase, suggesting that hormones may influence the balance of hemispheric activation. Such influences might at least in part be responsible for more variable results with female than with male subject groups and for contradictions between different experiment studies. ... With respect to overall speed of processing the results for face decisions indicate that during menstruation and especially during the prementrual phase, the processing of such stimuli seems to be more difficult than in the middle of the cycle, where reactions were faster and fewer errors were made (see Fig. 3). This fits rather well with reports in the literature demonstrating better performance (and lower visual thresholds in midcycle, probably due to the activating effects of oestogen. However, it is difficult to compare results because of the many different ways of defining cycle phases, and the various measures and tasks employed in the literature. Our finding of faster more correct responses in midcycle is also in certain agreement with Hampson's and Hampson and Kimura's result that speed and accuracy on nonverbal tasks were better during the luteal than during the menstrual phase. If one compares the results of Experiments I and II one realizes that during the menstrual, follicular and luteal phases face decisions tended to be faster overall than lexical decisions, while during the premenstrual phase face decisions were much slower overall than the verbal ones. The premenstrual phase showed at the same time the fastest verbal and the slowest non-verbal responses of all phases of the menstrual cycle. [study done in Germany]" (Heister, G., Landis, R., Regard, M. & Schroeder-Heister, P. (1989) Shift of functional cerebral asymmetry during the menstrual cycle. Neuropsychologia 27: 877))

"The main result of our study is the linear decrease of left field superiority for face decisions, as measured from menstuation (during which pituitary and gonadal hormones are low) to what we here call the premenstrual phase, where---compared with the other phases----in particular the progesterone level should be high. That is, even with respect to asymmetry, a change takes place in the premenstrual phase. Our hypothesis that the largest asymmetry, a relatively "male pattern" of lateralization, should be found during menstruation when female sex hormones are extremely low, was supported. As compared to the menstrual phase, during the premenstrual phase 10 of the 12 subjects showed a smaller or even reversed asymmetry for this task. The reliability of our findings is also supported by the analysis of errors, which yielded the same pattern of results as reaction times, that is , a shift of asymmetry in the prementrual phase. Since the main difference was obtained between the menstrual and premenstrual phases and not between the menstrual and follicular phases, one may speculate that the result is related to progesterone, since oestrogen has one peak during the follicular phase and one during the luteal phase and should be lower during the premenstrual phase." (Heister, G., Landis, R., Regard, M. & Schroeder-Heister, P. (1989) Shift of functional cerebral asymmetry during the menstrual cycle. Neuropsychologia 27: 877-8)