Prolactin pulsatile characteristics in postmenopausal women.

Pulsatile PRL secretion undergoes diurnal variation, with maximal PRL release in the evening during sleep in both women and men. However, the impact of the menopause on PRL pulsatile dynamics are largely unknown. To characterize diurnal PRL pulsatile secretion in postmenopausal women, we performed frequent venous sampling over 24 h every 10 min for serum PRL in 7 postmenopausal women (age, 56 +/- 4 yr) and in 2 control groups, 8 men (age, 25 +/- 8 yr) and 22 cycling women (age, 28 +/- 5 yr), at 3 phases of the menstrual cycle. Standard TRH tests (200 microg, i.v.) were administered at 0900 h after completion of the 24-h sampling, and PRL levels were then obtained at 0, 10, 20, 30, and 60 min in all subjects. PRL pulse characteristics were similar between the postmenopausal women and men. Mean serum PRL levels and PRL pulse frequency were significantly higher in the cycling women than in either postmenopausal women or men over 24 h and during either the day or night periods. Mean serum PRL levels and pulse frequency were significantly higher during the night compared to those during the day in all groups. Pulse amplitude was higher during the night vs. the day in all groups and was highest in the cycling women. PRL responses to TRH administration were greatest in cycling women. These data demonstrate that PRL pulse dynamics are significantly different between postmenopausal women and cycling women, and endogenous estrogen levels may have an important role in this difference. Pulsatile PRL secretion is similar between postmenopausal women and men, suggesting that estrogen levels modulate PRL dynamics across genders.

The effects of estrogen administration on trabecular bone loss in young women with anorexia nervosa.

To study the effects of prolonged anorexia nervosa on bone density (BD) and to determine whether estrogen administration prevents bone loss in women with this disorder, 48 amenorrheic women with anorexia nervosa (mean age, 23.7 yr) were randomized to receive estrogen and progestin replacement (n = 22) or no replacement (n = 26). Clinical variables, biochemical indices, and spinal trabecular BD were measured every 6 months for a mean of 1.5 yr. Initial mean BD (130 +/- 27 mg K2HPO4/cm3, +/- 1 SD) was significantly (P < 0.001) less than normal (176 +/- 26 mg K2HPO4/cm3) and less than 2 SD below normal in 21 of the 48 women. Forty-four women completed the study (19 in the estrogen group and 25 in the control group). The mean duration of follow-up was comparable in the estrogen-treated (1.57 +/- 0.89 yr) vs. the control group (1.41 +/- 0.69 yr). The estrogen-treated group had no significant change in BD compared with the control group; however, there was a 4.0% increase in mean BD in patients with an initial ideal body weight of less than 70% who were treated with estrogen. In contrast, control patients with comparably low initial weight had a 20.1 % decrease in BD. Women in the control group with spontaneous resumption of menses, all of whom had an initial percent ideal body weight of greater than 70%, had a 19.3% increase in bone mass. It is concluded that: 1) estrogen replacement cannot prevent progressive osteopenia in young women with anorexia nervosa; 2) a subset of patients may have improved BD with estrogen and progestin administration depending on initial body weight; and 3) recovery from anorexia nervosa is associated with significantly improved BD.

Progressive trabecular osteopenia in women with hyperprolactinemic amenorrhea.

Reductions in cortical and trabecular bone mass have been documented in young women with hyperprolactinemic amenorrhea. It is unknown whether trabecular osteopenia is progressive or reversible with treatment of hyperprolactinemia. In addition, it is not known whether clinical or hormonal variables can predict trabecular bone density (BD) changes. Therefore, we investigated prospectively trabecular BD by computed tomography in 52 hyperprolactinemic women and 41 controls. The mean follow-up interval was 1.8 +/- 0.1 (SEM) yr. Patient groups were defined as follows: group 1, amenorrhea during the entire study; group 2, restoration of menses during the study by treatment of hyperprolactinemia; group 3, regular menses despite hyperprolactinemia, with no history of prior amenorrhea; group 4, history of prior amenorrhea, but menses restored with treatment of hyperprolactinemia before study entry; and group 5, oligomenorrhea. Groups 1, 2, and 4 had significant (P = 0.0006) initial spinal osteopenia [mean BD 141 +/- 7 (SEM), 144 +/- 9, and 151 +/- 5 mg/cc K2HPO4, respectively] compared with controls or with group 3 (170 +/- 4 and 173 +/- 8 mg/cc K2HPO4, respectively). Group 5 had an initial mean BD which was midway between that of the amenorrheic and eumenorrheic women (156 +/- 13 mg/cc K2HPO4). Group 1 had a significant (P = 0.04) decrease in mean BD to 132 +/- 8 mg/cc K2HPO4 over 1.7 +/- 0.2 yr, with BD in 42% of the group more than 2 SD below the control mean at the final study point. The mean BD in group 2 increased to 155 +/- 9 mg/cc K2HPO4, approaching significance (P = 0.07) when compared with the initial BD. Five of the nine patients in this group (56%) had an increase in BD greater than the variation expected for the computed tomography technique. However, 44% of the group 2 patients had a spinal BD which remained more than 1 SD below the normal mean. There was no change in BD in the other groups.(ABSTRACT TRUNCATED AT 400 WORDS)

The effect of amoxapine and imipramine on serum prolactin levels.

The effect of traditional tricyclic antidepressants on serum prolactin levels is controversial. In a five-week double-blind study of depressed outpatients, imipramine hydrochloride therapy did not lead to any significant change in serum prolactin levels. In contrast, amoxapine, a new antidepressant, produced significant elevations in serum prolactin levels in female and in male patients. Amoxapine may block dopamine receptors in central tuberoinfundibular pathways, which would account for its prolactin-elevating activity. On the other hand, imipramine and other traditional tricyclic antidepressants do not affect dopamine transmission, do not raise serum prolactin levels, and are not effective antipsychotic drugs.