A selective serotonin reuptake inhibitor, fluoxetine hydrochloride, modulates the pulsatile release of prolactin in postmenopausal women

Article Abstract:

To learn more about the control and regulation of prolactin (a hormone produced by the pituitary gland that stimulates milk production during pregnancy) by serotonin, a neurotransmitter, seven healthy postmenopausal women were studied. Postmenopausal women were selected because they lack significant levels of other female hormones (such as estradiol) that could also have affected prolactin levels. The subjects received either fluoxetine (an agent that potentiates the effects of serotonin by inhibiting its reuptake into the nerve terminal) or a placebo pill three times daily for six days before each study session. The study design allowed each subject to function as her own control; the women received either drug or placebo at each of two separate sessions several weeks apart. Blood samples were obtained for prolactin measurements every 10 minutes over one 24-hour period after drug administration. Results showed an increase in the blood levels of prolactin after fluoxetine, as well as increases in the maximum peak prolactin levels and the maximum valley (lowest) levels. The mass of prolactin excreted also increased after fluoxetine. Other pharmacologic parameters are described. It seems that serotonin increases blood prolactin concentrations by modifying the amplitude of prolactin secretory ''bursts'', rather than affecting the frequency of these bursts or their overall daily rhythm. Serotonin also seems able to affect prolactin secretion even when certain female hormones are no longer present in significant amounts. (Consumer Summary produced by Reliance Medical Information, Inc.)

Postmenopausal women, Fluoxetine, Serotonin

---

Mechanisms that subserve estradiol's induction of increased prolactin concentrations: evidence of amplitude modulation of spontaneous prolactin secretory bursts

Article Abstract:

Prolactin is a hormone secreted by the pituitary gland. In combination with a network of other hormones, prolactin helps to develop the mammary glands and is involved in the production of breast milk. Prolactin secretion is affected by the release of estrogen, the hormone released by the ovaries. Other hormones secreted by the pituitary gland are released periodically in a rhythmic fashion. When estrogen is released in quantity, prolactin levels increase. To determine the pattern of prolactin release estradiol, a form of estrogen, was given to six healthy menopausal women. Since menopausal women no longer secrete estrogen on their own, this was an appropriate model for studying the release of prolactin. A plastic ring impregnated with estradiol was placed in the vagina and periodic blood samples were obtained to measure prolactin secretion. The results indicate that estrogen selectively increases the amplitude of periodic prolactin secretion without changing the frequency of the hormone bursts or decreasing the time it takes for prolactin to dissipate. It is this way that estradiol mediates prolactin release from the pituitary gland.

Hormone research, Estradiol

---

Characteristics of luteinizing hormone secretion in younger versus older premenopausal women

Article Abstract:

Endocrine changes outside of the ovaries may precede the loss of reproductive function in women at menopause. Researchers compared luteinizing hormone levels and dynamics in six women in their 20's and 12 middle-aged women. Older women had longer bursts of hormone secretion, longer intervals between peak hormone levels, a longer hormone half-life in the blood, and more orderly hormone secretion. This age-associated change may reflect a slowing of gonadotropin-releasing hormone activity, which acts in a feedback mechanism to regulate hormone levels.

Development and progression, Menopause, Gonadotropin releasing hormone, Gonadorelin, Luteinizing hormone, Middle aged women

Similar abstracts:

• Abstracts: A comparison of the effects of hydrochlorothiazide and captopril on glucose and lipid metabolism in patients with hypertension
• Abstracts: Pulmonary beta-adrenergic receptors and response do not mature precociously in growth-retarded rabbit fetuses
• Abstracts: Some new twists to one of the most common procedures in US general surgery. Lipid particles may help solve puzzle regarding genesis of some cardiovascular diseases
• Abstracts: DNA discoverer James Watson now dreams of curing genetic diseases. A few words of advice from a woman of letters - Ann Landers
• Abstracts: A longitudinal study of the relationship between placental and fetal growth as measured by ultrasonography. A randomized trial of plasma volume expansion in hypertensive disorders of pregnancy: Influence on the pulsatility indices of the fetal umbilical artery and middle cerebral artery

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.