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Biomedical subjects

E J Plotz

Publications and source records attributed to E J Plotz.

At least 19 recordsLinked to original sources
PubMed1980

Induction of ovulation with chronic intermittent (pulsatile) administration of LH-RH in women with hypothalamic and hyperprolactinemic amenorrhea.

Five women with hypothalamic amenorrhea were treated with LH-RH (10-15 microg i.v. at 90 min intervals for 17-20 days). In all women this chronic intermittent LH-RH administration resulted in a normalization of serum gonadotropin levels. Four women exhibited preovulatory estradiol serum levels with subsequent LH peaks. In three women the LH peaks were followed by normal luteal phase serum progesterone levels. One woman with hyperprolactinemic amenorrhea was also treated with the same therapeutic regimen which induced ovulation as judged from normal luteal phase serum progesterone levels. The results indicate that normal pituitary-ovarian function can be established in hypothalamic amenorrhea by chronic intermittent administration of LH-RH. They also suggest that in the human female hypothalamic LH-RH function may be only permissive in that the cyclicity of endocrine events during the menstrual cycle is regulated on pituitary and ovarian levels. Hyperproactinemic amenorrhea appears to be associated with insufficient endogenous LH-RH secretion which can be substituted by exogenous chronic intermittent administration of LH-RH. Elevated prolactin levels per se do not interfere with the pituitary positive feedback mechanisms nor with the gonadotropin action on the ovarian level.

Adult↗
PubMed1976

Experimental studies on the positive feedback effect of progesterone, 17 alpha-hydroxyprogesterone and 20 alpha-dihydroprogesterone on the pituitary release of LH and FSH in the human female. The estrogen priming of the progesterone feedback on pituitary gonadotropins in the eugonadal woman.

Administration of progesterone eugonadal women during the midfollicular phase of the menstrual cycle failed to induce a positive feedback effect on the serum concentrations of LH and FSH. The levels of estradiol in serum decreased following the injection of progesterone without a parallel change in LH and FSH concentrations indicating a direct ovarian effect of the exogenous progesterone. In the late follicular phase of the cycle, when preovulatory levels of estradiol were present in serum, or under a ethinyl estradiol treatment progesterone was able to induce an LH discharge indicating the requirement of an estradiol priming of the positive feedback of progesterone in eugonadal women. In order to establish the time required for a sufficient estrogen priming with preovulatory levels of estradiol in serum 3 mg of estradiol-benzoate were administered i.m. 1, 12 and 24 h prior to the administration of 30 mg of microcristalline progesterone in the midfollicular phase of the menstrual cycle, when progesterone alone did not cause an LH surge. Only when estradiol-benzoate was injected 24 h prior to the progesterone administration an LH surge reproducible in time course and magnitude occurred. Administration of estradiol-benzoate alone under these conditions did not cause an LH surge within the elapse of time after the injection when the progesterone induced LH surge occurred. Thus, these experiments demonstrate that a defined estrogen priming is required for the positive feedback effect of progesterone on the gonadotropin release in eugonadal women. Furthermore, progesterone levels in serum of about only 1--2 ng/ml were required for the induction of an LH surge indicating that under physiological conditions progesterone may have an supplementory effect on the primarily estradiol induced LH midcycle peak. 17-hydroxyprogesterone administered during the mid follicular phase of the menstrual cycle and under pretreatment with ethinyl estradiol failed to induce a positive feedback effect on the serum concentrations of LH and FSH, indicating that this steroid does not play a regulatory role on the midcycle LH release in women. 20alpha-dihydroprogesterone administered under the same experimental conditions as 17-hydroxyprogesterone seems to be able to induce an LH surge in serum provided there is an adequate estrogen priming.

20-alpha-Dihydroprogesterone↗
PubMed1975

[LH, FSH and ovarian steroids in serum during normal menstrual cycles and cycles with corpus luteum insufficiency in the human female (author's transl)].

LH, FSH, estradiol-17beta, progesterone, 20alpha-dihydroprogesterone, 17alpha-hydroxyprogesterone, delta4-androstenedione and testosterone are determined by radioimmunoassay in serum daily during 11 menstrual cycles. Three of them had to be considered as cycles with corpus luteum insufficiency on the basis of basal body temperature, length of the luteal phase and the pattern of progesterone concentration in serum. One woman conceived during the investigated cycle. The present concepts of the regulation of ovulation are discussed on the basis of the chronological relationshp of changing endocrine parameters in serum during the cycles. The analysis of the hormone concentrations in serum during the cycles with corpus luteum insufficiency supports the view that corpus luteum insufficiency could be caused by an insufficient stimulation of the growing follicle, but other ethiological factors have also to be considered.

Adult↗