The modulatory effect of catecholamines on gonadotropin-stimulated granulosa cell steroid secretion

Effects of ovarian dopaminergic receptors on ovulation

Hormonal and neural signals regulate the ovarian follicular development. The present study's hypothesis is that the blockade of ovarian dopamine receptors locally will affect follicle development and ovulation. Groups of adult 4-day cyclic rats of the CII-ZV strain on estrus, diestrus-1, diestrus-2, or proestrus day were injected with vehicle, haloperidol (DA2 > DA1 blocker), sulpiride (DA2 blocker), or SCH-23390 (DA1 blocker) into the bursa of both ovaries at 08:00, 13:00, or 20:00 h. Animals were sacrificed the following predicted estrus day. The following treatments blocked ovulation: injecting haloperidol to rats on estrus or diestrus-1 at 8:00, 13:00, or 20:00 h and to rats on diestrus-2 at 08:00, or 20:00 h; injecting SCH-23390 to rats on diestrus-1 at 8:00, 13:00, or 20:00 h; injecting sulpiride to rats on estrus at 20:00 h, diestrus-1 at 08:00, 13:00, or 20:00 h and to rats on diestrus-2 at 08:00 h. In rats treated with any of the dopamine antagonists that blocked ovulation, injecting GnRH at 14.00 h on the next predicted proestrus day restored ovulation. Injecting estradiol benzoate at 14.00 h of the next predicted diestrus-2 restored ovulation in some animals treated with haloperidol on estrus or diestrus-2 and was ineffective in rats treated on diestrus-1. In rats treated with sulpiride or SCH-23390 ovulation occurred in most animals (SCH-23390: 6/8; SPD: 9/12). Present results suggest that dopamine ovarian receptors' participation in regulating follicular development and ovulation varies along the estrus cycle, with their most prominent activity occurring on diestrus-1.

Perceived racial discrimination and risk of uterine leiomyomata

BACKGROUND

The incidence of uterine leiomyomata (fibroids, myomas) is 2-3 times higher in black women than white women. Black women also report higher levels of racial discrimination. We evaluated the hypothesis that greater exposure to racism increases myoma risk in black women.

METHODS

Data were derived from the Black Women's Health Study, a prospective cohort study of US black women age 21-69 years in 1995. In 1997, women reported on "everyday" and "lifetime" experiences of racism. From 1997 through 2003, we followed 22,002 premenopausal women to assess the association between self-reported racism and risk of myomas. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were estimated from Cox regression models.

RESULTS

During 107,127 person-years of follow-up, 3440 new cases of uterine myomas confirmed by ultrasound (n = 2774) or surgery (n = 666) were reported. All IRRs for "lifetime" and "everyday" experiences of racism were above 1.0. Using a summary variable that averaged the responses from 5 "everyday" racism items, multivariable IRRs comparing quartiles 2, 3, and 4 to quintile 1 (lowest) were 1.16 (95% CI = 1.04-1.29), 1.19 (1.06-1.32), and 1.27 (1.14-1.43), respectively. Multivariable IRRs comparing women who reported 1, 2, or 3 lifetime occurrences of major discrimination (ie, job, housing, or police) relative to those who reported none were 1.04 (0.96-1.13), 1.17 (1.07-1.28), and 1.24 (1.10-1.39), respectively. Results did not vary according to case definition (ultrasound vs. surgery) or health care utilization. Associations were weaker among foreign-born women and among women with higher coping skills.

CONCLUSIONS

Perceived racism was associated with an increased risk of uterine myomas in US-born black women.

Dexamethasone-induced Changes in Sympathetic Innervation of Porcine Ovaries and in Their Steroidogenic Activity

The aim of the present study was to determine changes in the density of sympathetic nerves in porcine ovaries with dexamethasone (DXM)-induced cysts and the alterations in steroidogenic activity and amounts of catecholamines in the affected gonads. Cystic ovaries were supplied by numerous sympathetic nerve fibers. The amount of noradrenaline in the cysts (fluid, wall) was significantly higher than in the large follicles of the control group. After DXM injections, the amounts of noradrenaline and adrenaline significantly increased in the walls of small and medium-sized follicles. In the cysts (fluid, wall) the levels of androgens and estrogens were significantly lower, whereas progesterone was higher in the cystic wall. DXM administration led to a significant increase in the estrone content in the fluid of small follicles. Moreover, a decrease in the amounts of progesterone and androgens was found in the follicular fluid and walls of medium-sized follicles. DXM injections resulted in a significant increase in the immunoexpression of P450(scc) and 3beta-HSD in the cysts, a significant increase of P450(scc) in the follicles, and a decrease of 3beta-HSD and P450(arom). The present study shows that the DXM treatment leads to an increase in the density of intraovarian sympathetic nerves, paralleled by the amount of catecholamines, and that it is capable of changing the steroidogenic activity of porcine ovary bearing cysts. Thus, it appears possible that these events may be, at least partly, involved in the pathogenesis of this disorder.