BIOLOGICALLY ACTIVE LUTEINIZING HORMONE (LH) IN PLASMA: II. COMPARISON WITH IMMUNOLOGICALLY ACTIVE LH LEVELS THROUGHOUT THE HUMAN MENSTRUAL CYCLE

1977 ◽  
Vol 84 (4) ◽  
pp. 697-712 ◽  
Author(s):  
P. Romaní ◽  
D. M. Robertson ◽  
E. Diczfalusy
Keyword(s):  
Menstrual Cycle ◽  
Luteinizing Hormone ◽  
Plasma Levels ◽  
Biologically Active ◽  
Dose Effect ◽  
Confidence Limits ◽  
Human Pituitary ◽  
17 Hydroxyprogesterone ◽  
Human Menstrual Cycle

ABSTRACT The levels of biologically active luteinizing hormone were determined by an in vitro bioassay method in plasma samples collected daily over a complete menstrual cycle from 12 menstruating women. These cycles were normal according to a number of criteria, including daily plasma levels of oestradiol, 17-hydroxyprogesterone and progesterone. Immunoreactive LH was estimated in the same 12 cycles by a radioimmunoassay (RIA) procedure (HCG-RIA) using an HCG antiserum and iodinated HCG. The 2nd IRP of HMG was selected as standard although significant deviations from parallelism were found with 7 out of the 12 plasma pools studied. The use of the 1st IRP of human pituitary gonadotrophins (FSH and LH (ICSH)) for bioassay (hereafter HPG-1st IRP) as standard in this system resulted invariably in invalid assays, due to lack of parallelism. Immunoreactive LH was also measured in 8 of the 12 cycles by a RIA procedure (HLH-RIA) using a human LH antiserum and iodinated human LH of pituitary origin. Results are expressed in terms of the HPG-1st IRP. The plasma levels of biologically and immunologically active LH were qualitatively similar throughout the menstrual cycle. However, the LH levels measured by the bioassay invariably exceeded those estimated by the RIA procedures. The biological to immunological (B/I) ratio over the entire menstrual cycle (312 comparisons) was 5.5 with 95% confidence limits at 5.2 and 5.8 when the HCG-RIA system was employed. Using the HLH-RIA system (208 comparisons), the corresponding ratio was 6.4 (6.0:6.9). When regression lines were calculated using the bioassay results as the independent variable and the RIA results as the dependent variable, the 95% confidence limits of the regression lines did not include the origin. Furthermore, in keeping with the high B/I ratios, the slopes of the two regression lines and their confidence limits differed markedly from unity. It is concluded that although qualitatively similar profiles were observed between the biological and immunological activities throughout the menstrual cycle, two aspects require further attention. Firstly, the elevated B/I ratios together with the behaviour of the dose-effect lines obtained with different standards in the various RIA systems suggest that presently available reference standard preparations of pituitary and/or urinary origin are not suitable for the assay of LH in human plasma. Secondly, from the regression analyses of the biological and immunological activities it is inferred that the RIA methods detect immunological activity which is not associated with biological activity. If so, the validity of these RIA procedures for specifically measuring low levels of biologically active LH in plasma may be in question.

LUTEINIZING HORMONE LEVELS DURING THE MENSTRUAL CYCLE OF THE BABOON (PAPIO HAMADRYAS)

1979 ◽  
Vol 91 (1) ◽  
pp. 49-58 ◽  
Author(s):  
N. Goncharov ◽  
A. V. Antonichev ◽  
V. M. Gorluschkin ◽  
L. Chachundocova ◽  
D. M. Robertson ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Luteinizing Hormone ◽  
Plasma Levels ◽  
Luteal Phase ◽  
Follicular Phase ◽  
Papio Hamadryas ◽  
Biologically Active ◽  
Plasma Progesterone ◽  
Lh Surge

ABSTRACT The peripheral plasma levels of luteinizing hormone (LH) as measured by an in vitro bioassay method were determined in daily plasma samples collected throughout one menstrual cycle in 8 normally menstruating baboons (Papio hamadryas). In addition LH was measured in plasma at three hourly intervals throughout the day in the follicular, peri-ovulatory and luteal phases of the cycle in 7, 3 and 6 animals respectively. The plasma levels of progesterone and oestradiol were also determined in the same samples throughout the menstrual cycle and during the period of the midcycle LH surge. The circulating LH profile measured throughout the cycle was characterized by a sharp mid-cycle surge (completed within one day) which was followed by a series of LH surges of varying intensity during the luteal phase of the cycle. The initial surge was considered to be pre-ovulatory as indicated by its relationship to the peak of plasma oestradiol and to the first significant increase in the levels of plasma progesterone above values found earlier in the follicular phase. A circadian rhythm of LH was observed during the luteal phase of the cycle; a 3 fold rise in LH was noted during the hours 15.00 to 24.00. No differences were observed throughout the day in the follicular phase of the cycle. The LH profile in three animals studied during the mid-cycle LH surge showed pronounced circadian changes with a major peak at 24.00 h. Plasma progesterone levels during this period rose sharply to values normally found in the mid-luteal phase of the cycle. A comparison of plasma levels of biologically active LH during the menstrual cycle of the baboon with those found in normally menstruating women reveals that in the baboon the LH peak is of much shorter duration and the levels in the follicular and peri-menstrual phases are significantly lower than in the human.

THE INTERNATIONAL REFERENCE PREPARATION OF HUMAN PITUITARY LUTEINIZING HORMONE, FOR IMMUNOASSAY

1978 ◽  
Vol 88 (2) ◽  
pp. 250-259 ◽  
Author(s):  
P. L. Storring ◽  
D. R. Bangham ◽  
P. Mary Cotes ◽  
Rose E. Gaines ◽  
S. L. Jeffcoate
Keyword(s):  
Luteinizing Hormone ◽  
Reproductive Organ ◽  
Expert Committee ◽  
Confidence Limits ◽  
Binding Assays ◽  
Human Pituitary ◽  
International Reference ◽  
Biological Standardization ◽  
Reference Preparation

ABSTRACT The preparation and nature of the International Reference Preparation of Human Pituitary Luteinizing Hormone for Immunoassay are described. A collaborative assay of this material (coded 68/40) in terms of the International Reference Preparation of Human Pituitary Gonadotrophins (FSH and LH (ICSH)), for Bioassay (coded 69/104) was carried out by twelve laboratories in seven different countries, using different bioassay and immunoassay methods. The weighted combined potency estimate (with 95 % confidence limits) was 52.1 (46.3–58.7) IU/ampoule with male accessory reproductive organ weight gain assays; 80.2 (73.2–87.9) IU/ampoule with ovarian ascorbate depletion assays; 127 (124–129) IU/ampoule with in vitro Leydig cell testosterone production assays; and 124 (121–126) IU/ampoule with testis receptor binding assays. Immunoassay estimates in terms of the same standard were heterogeneous and gave an unweighted mean potency estimate of 33.2 IU with 95% confidence limits of 14.8– 74.4 IU/ampoule. Estimates from different methods gave significantly different results, and the reasons for this are discussed in terms of the differences between the materials being compared and the methods used in the comparison. These data illustrate the conceptual difficulties involved in comparing hetero geneous reference preparations, especially by both bioassay and immunoassay, and some of the causes of inevitable discontinuity of assay results, as described in the 26th Report of the WHO Expert Committee on Biological Standardization. On the basis of these results, and in the interest of maintaining continuity of its unitage, the International Reference Preparation has been allocated a potency of 77 IU/ampoule.

BIOLOGICALLY ACTIVE LUTEINIZING HORMONE (LH) IN PLASMA

1979 ◽  
Vol 92 (4) ◽  
pp. 615-626 ◽  
Author(s):  
D. M. Robertson ◽  
Vipla Puri ◽  
Monica Lindberg ◽  
E. Diczfalusy
Keyword(s):  
Individual Differences ◽  
Menstrual Cycle ◽  
Luteinizing Hormone ◽  
Active Material ◽  
Biologically Active ◽  
Plasma Samples ◽  
Human Pituitary ◽  
Significant Drop ◽  
Lh Surge ◽  
Sources Of Variation

ABSTRACT The relationship between the biological and immunological activities of human luteinizing hormone (hLH) in plasma collected from female subjects was examined. The biological activity was measured by an in vitro bioassay and the immunological activity by an hLH radioimmunoassay (RIA), using improved reagents, such as the 1st IRP for human pituitary LH for immunoassay (code No. 68/40) as standard, a subunit-free biologically active iodinated hLH preparation as tracer and an anti-hLH serum of relatively high specificity. Similar profiles of biological (B) and immunological (I) activity were obtained in the plasma samples collected daily throughout 40 menstrual cycles (5 cycles from each of 8 subjects). However, the B/I ratios were significantly lower during the period of LH surge (P < 0.001) than throughout the remainder of the cycle. The within- and between-assay variation in B/I ratios was investigated by the simultaneous assay of biological and immunological activities in plasma pools obtained by combining equal aliquots of plasma from each daily sample of the menstrual cycle from each of 5 cycles of each of 4 subjects. The analysis of these 20 pools revealed highly significant individual differences in B/I ratios, ranging from 0.81 to 1.33. The coefficient of variation was 20 % between-subjects and 5 % within-subjects. There was no seasonal variation in B/I ratios. That the individual differences in plasma B/I ratios were not attributable to the procedure of pooling was ascertained by the simultaneous assay of both activities in parellel in daily plasma samples and in the pools formed from these samples from three complete cycles. Thus the analysis of the differences in B/I ratios obtained throughout the menstrual cycle revealed three major sources of variation. The first occurs in the form of generally elevated (higher than unity) B/I ratios, the second consists of a significant drop in B/I ratios during the midcycle LH surge, and the third source is represented by the significant between-subject differences. It is concluded that the first source is attributable to the relatively higher levels of "impurity" (i.e. biologically inactive, immunologically active material) in the standard preparation compared to those present in plasma, whereas the other sources are due most probably to the presence in plasma of biologically inactive, immunologically active material of unknown composition and origin. If so, the latter source limits the quantitative significance of the RIA procedures employed. It is suggested that these three sources of variation account for most of the differences in B/I ratios for plasma hLH reported in the literature.

Biologically Active Luteinizing Hormone Is Secreted in Episodic Pulsations that Vary in Relation to Stage of the Menstrual Cycle*

1984 ◽  
Vol 58 (6) ◽  
pp. 1050-1058 ◽  
Author(s):  
JOHANNES D. VELDHUIS ◽  
INESE Z. BEITINS ◽  
MICHAEL L. JOHNSON ◽  
MERCEDES A. SERABIAN ◽  
MARIA L. DUFAU
Keyword(s):  
Menstrual Cycle ◽  
Luteinizing Hormone ◽  
Biologically Active

Intrinsic Pulsatility of Luteinizing Hormone Release from the Human Pituitary in Vitro

1988 ◽  
Vol 43 (1) ◽  
pp. 49-50
Author(s):  
MARCO GAMBACCIANI ◽  
JAMES H. LIU ◽  
WILLIAM H. SWARTZ ◽  
VICKI S. TUEROS ◽  
SAMUEL S. C. YEN ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Hormone Release ◽  
Human Pituitary ◽  
Luteinizing Hormone Release

The relation of serum 17-hydroxyprogesterone and estradiol-17β levels during the human menstrual cycle

1971 ◽  
Vol 111 (7) ◽  
pp. 947-951 ◽  
Author(s):  
Ian H. Thorneycroft ◽  
Daniel R. Mishell ◽  
Sergio C. Stone ◽  
Khalil M. Kharma ◽  
Robert M. Nakamura
Keyword(s):  
Menstrual Cycle ◽  
17 Hydroxyprogesterone ◽  
Human Menstrual Cycle ◽  
Estradiol 17Β

BIOLOGICALLY ACTIVE LUTEINIZING HORMONE (LH) IN PLASMA

1976 ◽  
Vol 83 (3) ◽  
pp. 454-465 ◽  
Author(s):  
P. Romaní ◽  
D. M. Robertson ◽  
E. Diczfalusy
Keyword(s):  
Menstrual Cycle ◽  
Dose Response ◽  
Gel Filtration ◽  
Biologically Active ◽  
Relative Potency ◽  
Response Curves ◽  
Plasma Pool ◽  
Dose Response Curves ◽  
Post Menopausal

ABSTRACT A recently described in vitro bioassay method for the measurement of biologically active LH (Van Damme et al. 1974) has been applied to the plasma of normally menstruating and post-menopausal women. The specificity of the procedure was established according to the following evidence: 1. Parallelism was observed between dose response curves obtained with serial dilutions of a standard LH preparation (HMG 2nd IRP) and plasma pools collected during the follicular phase, at the LH-peak, during the luteal phase and after menopause. 2. There was no evidence for the presence of any synergistic or antagonistic factor in the various plasma specimens. The assay design used to establish this consisted of assaying the standard and plasma pool separately and then together as a mixture followed by an asssessment of the difference (if any) in the potencies obtained. Strict additivity should yield a relative potency of 1.0. Plasma pools which were obtained every 2–3 days throughout the menstrual cycle were assayed using this design against the standard (HMG 2nd IRP) and against a mid-cycle plasma pool obtained at the time of the LH-peak. The latter was also assayed against partially purified plasma fractions obtained from a post-menopausal plasma pool after gel filtration and isoelectric focusing. With the exception of 3 assays, in which the estimates of relative potency were 0.91, 0.94 and 0.95, respectively, in 19 assays of additivity, the fiducial limits always included unity. 3. Non-detectable LH levels were found in the plasma or serum of either hypophysectomized or hypopituitary hypogonadal men or women treated with oestrogen/progestogen combined pills. 4. The presence of calf or human serum in the assay medium is an essential requirement for a valid comparison of standard and unknown preparations. In their absence, non-parallel dose response curves between plasma and standard were obtained. The other established criteria of reliability (sensitivity and precision) were also examined. The method is sufficiently sensitive (3.5–8.0 mIU/ml plasma; HMG (2nd IRP) as standard) for the measurement of LH throughout the cycle. The mean index of precision (λ) in 230 multiple assays was 0.040. It is concluded that the modified bioassay yields valid and reliable estimates of LH when applied to human plasma obtained throughout the menstrual cycle and after menopause.

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