Follicle-stimulating hormone and luteinizing hormone in serum during the menstrual cycle determined by radioimmunosassay

Abolition of endocrine dimorphism in hyperthyroid males? An argument for the positive feedback effect of hyperoestrogenaemia on LH secretion

Our aim was (i) to investigate the hypothalamo-hypophyseal-gonadal axis in hyperthyroid Indian males, (ii) to rule out the modulatory role of adrenal steroids on it and (iii) to determine if the simultaneous rise in oestradiol and luteinising hormone (LH) in hyperthyroid males is due to a positive feedback action of oestradiol on pituitary LH release. Age- and BMI-matched men were divided into two groups, I, euthyroid subjects (n = 17) and II, hyperthyroid patients (n = 12) on the basis of their thyroid hormone levels. Serum levels of thyroid-stimulating hormone, triiodothyronine, thyroxine, LH, follicle-stimulating hormone (FSH), prolactin, E(2), T, P(4), sex hormone binding globulin and dehydroepiandrosterone sulphate (DHEAS) were assayed. Mean levels of T and E(2) were approximately two times higher in group II in comparison with group I. DHEAS levels were similar in both groups ruling out any adrenal involvement. Mean serum LH level was 2.6 folds higher in group II in comparison with group I. Mean serum levels of FSH were higher in group II, it was marginally nonsignificant. On the basis of these and previous observations, we hypothesise that endocrinological dimorphism in human male and female is not rigid; a sustained rise in serum oestradiol probably induces a positive feedback action on pituitary leading to elevated gonadotrophin levels.

The value of simple tests in the detection of human ovulation

Cervical mucus viscosity (CMV) and fern test (FT), leukocyte alkaline phosphatase (LAP) activity, basal body temperature (BBT) and serum luteinizing hormone (LH) levels were determined during 31 normal menstrual cycles of 29 volunteers. The day of the serum LH surge was taken as a reference point in evaluating the reliability and sensitivity in predicting ovulation of the other tests studied. Serum LH surge was accompanied by a sudden decrease in CMV, an increase in LAP activity, a gradual increase in FT and biphasic changes of BBT. In about 95% of cycles studied, the lowest values of CMV and peak values of LAP activity appeared on the day of the serum LH surge or one day before or one day after. The lowest point of the BBT coincided with the LH surge in only 26% of cycles. In 53% of cycles, the span was greater than one day before or after the LH peak. The FT corresponded to the LH surge in only 33% of the cycles, while in an additional 33% the preovulatory FT response occurred more than one day before or after the LH surge. The results indicate that CMV and LAP tests are rapid, simple and reliable for monitoring follicular maturation and the timing of ovulation when carried out daily, and may be of value in monitoring treatment during the induction of ovulation.

Pituitary gonadotropin responses to synthetic luteinizing hormone-releasing hormone in patients with typical and atypical polycystic ovary disease

Synthetic luteinizing hormone-releasing hormone (LH-RH) was administered intravenously to 17 women with polycystic ovary disease (PPCO), 16 women with hypothalamic amenorrhea (HA), and nine women with normal cycles. The serum levels of follicle-stimulating hormone (FHS) and luteinizing hormone (LH) were measured at frequent intervals before and after LH-RH injection. The PCO patients were arbitrarily divided into two groups on the basis of ovarian morphology. The eight patients with large, "typical" PCO's (Type I) showed a greater LH response and a lower FSH response to LH-RH than did the nine patients with smaller, "atypical" PCO's (Type II). The LH response in Type I co was also greater than that in HA, but the FSH response in both types of PCO was significantly less than that in HA. The gonadotropin responses to LH-RH in Type I PCO were quite similar to those occurring in normal women during the two to three days prededing ovulation. The results suggest that excessive LH secretion and/or impaired FSH secretion may be etiologically significant in PCO but do not clearly differentiate whether the stimulus for this pattern of gonadortopin secretion occurs at the hypothatamic or pituitary level.

[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.